Taxonomy

175. An organism has many cells, no cell wall and depends on other organisms for nutrition. Which kingdom fits it?

[RRB Group D 2025 recruitment, 21 Aug 2026 Shift 2]

(A) Fungi

(B) Plantae

(C) Animalia

(D) Monera

Answer: (C) Animalia

Explanation: Members of Animalia are multicellular eukaryotes without rigid cell walls and are heterotrophic. Plants have cellulose walls and generally photosynthesize, while fungi have chitin-containing walls. Monerans are prokaryotic and principally unicellular.

174. Two bacteria share an order but belong to different families. Which higher taxonomic categories must they share?

[RRB Group D 2025 recruitment, 20 Aug 2026 Shift 1]

(A) Only the order

(B) Order and family

(C) Only the family

(D) Order and class

Answer: (D) Order and class

Explanation: An order is nested inside a class, which lies inside a phylum and a kingdom. Organisms belonging to the same order therefore share every rank above it, though they may occupy separate families, genera and species.

173. Two animals belong to the same taxonomic order but different families. What follows?

[RRB Group D 2025 recruitment, 13 Aug 2026 Shift 1]

(A) They must belong to the same species

(B) They share a family but not a class

(C) They share all higher ranks through order

(D) They share a genus but not a family

Answer: (C) They share all higher ranks through order

Explanation: Taxonomic categories form a hierarchy. Sharing an order implies a shared class, phylum and kingdom, because each order sits wholly within those higher groups. Different families do not imply a shared genus or species.

172. What feature made Amoeba difficult to place in the old two-kingdom classification?

[RRB Group D 2025 recruitment, 11 Aug 2026 Shift 2]

(A) It is photosynthetic and multicellular

(B) It has no wall and never moves

(C) It has a nucleus but is autotrophic

(D) It is unicellular, motile and heterotrophic

Answer: (D) It is unicellular, motile and heterotrophic

Explanation: The traditional plant-animal division poorly accommodated microorganisms combining varied traits. Amoeba is one-celled, moves through pseudopodia and ingests food, but is a eukaryote unlike bacteria. The later Protista grouping addressed such classification problems.

171. DNA evidence reveals that two of three previously grouped microbes are closer relatives. What taxonomic change is most appropriate?

[RRB Group D 2025 recruitment, 13 Aug 2026 Shift 2]

(A) Ignore the genetic results

(B) Regroup them according to DNA similarity

(C) Keep the old grouping automatically

(D) Group them only by habitat

Answer: (B) Regroup them according to DNA similarity

Explanation: Molecular sequences give evidence of evolutionary relatedness. When genetic results contradict superficial resemblance, taxonomists may revise genera or other ranks so that classification more accurately reflects shared ancestry rather than convergent traits or habitats.

170. A photosynthetic unicellular organism has no membrane-bound nucleus. In Whittaker’s system, which kingdom contains it?

[RRB Group D 2025 recruitment, 03 Aug 2026 Shift 2]

(A) Fungi

(B) Monera

(C) Protista

(D) Plantae

Answer: (B) Monera

Explanation: Photosynthetic cyanobacteria are prokaryotes and were placed in Monera. They carry pigments and perform photosynthesis but lack a membrane-bound nucleus and chloroplasts. Protista comprises nucleated unicellular organisms, whereas Plantae consists predominantly of multicellular autotrophs.

169. Under Haeckel’s three-kingdom system, bacteria were placed in which newly recognised kingdom?

[RRB Group D 2025 recruitment, 09 Aug 2026 Shift 1]

(A) Protista

(B) Plantae

(C) Monera

(D) Animalia

Answer: (A) Protista

Explanation: Haeckel added Protista to the earlier plant-animal scheme to include microorganisms that did not fit either category. The separate Monera kingdom for prokaryotes appeared in subsequent classification systems, making Protista the historical answer here.

168. A spore-forming eukaryotic pathogen has a wall containing chitin. What is it?

[RRB Group D 2025 recruitment, 05 Aug 2026 Shift 3]

(A) Fungus

(B) Alga

(C) Bacterium

(D) Protozoan

Answer: (A) Fungus

Explanation: Chitin is a characteristic structural constituent of fungal walls. Fungi absorb nutrients and commonly form spores. Although some algae and protozoa are eukaryotic, these features together favour a fungus rather than a prokaryotic bacterium.

167. Where should a motile, unicellular eukaryote that engulfs bacteria be classified in the five-kingdom system?

[RRB Group D 2025 recruitment, 21 Aug 2026 Shift 3]

(A) Fungi

(B) Monera

(C) Animalia

(D) Protista

Answer: (D) Protista

Explanation: Protozoan protists are eukaryotic and usually single-celled. Many move and ingest food particles, much like Amoeba. Animalia includes multicellular heterotrophs, whereas Monera lacks a true nucleus; fungal nutrition is generally absorptive.

166. A vascular land plant has neither seeds nor flowers. Which plant group is indicated?

[RRB Group D 2025 recruitment, 12 Aug 2026 Shift 3]

(A) Pteridophyta

(B) Bryophyta

(C) Gymnosperms

(D) Angiosperms

Answer: (A) Pteridophyta

Explanation: Ferns and other pteridophytes possess conducting tissues, differentiated roots, stems and leaves, but reproduce by spores rather than seeds. Bryophytes lack true vascular tissue, while gymnosperms and angiosperms produce seeds.

165. A specimen has xylem and phloem but no seeds. Which plant division does it represent?

[RRB Group D 2025 recruitment, 10 Aug 2026 Shift 2]

(A) Gymnosperms

(B) Thallophyta

(C) Bryophyta

(D) Pteridophyta

Answer: (D) Pteridophyta

Explanation: The combination of developed vascular tissue with absence of seeds identifies pteridophytes. They include ferns, horsetails and allies. Bryophytes lack xylem and phloem; seed-bearing gymnosperms are vascular but do not meet the seedless condition.

164. One vascular plant bears cone seeds and another has seeds inside fruits. What are their respective groups?

[RRB Group D 2025 recruitment, 14 Aug 2026 Shift 3]

(A) Gymnosperm and angiosperm

(B) Bryophyte and gymnosperm

(C) Angiosperm and pteridophyte

(D) Pteridophyte and bryophyte

Answer: (A) Gymnosperm and angiosperm

Explanation: Gymnosperms bear naked seeds, commonly on cone scales, without enclosure by a ripened ovary. Angiosperms are flowering plants in which the ovary becomes a fruit enclosing the seeds, providing the diagnostic difference.

163. Which plant group has naked seeds and ordinarily does not require external water for fertilisation?

[RRB Group D 2025 recruitment, 21 Aug 2026 Shift 1]

(A) Bryophytes

(B) Pteridophytes

(C) Gymnosperms

(D) Angiosperms

Answer: (C) Gymnosperms

Explanation: Gymnosperms develop exposed ovules and seeds, and pollen conveys the male gametophyte, avoiding the free-water requirement characteristic of bryophytes and ferns. Angiosperms also use pollen but enclose their seeds within fruits.

162. A plant has vascular tissue yet needs free water for reproduction. Which division is most likely?

[RRB Group D 2025 recruitment, 19 Aug 2026 Shift 3]

(A) Pteridophyta

(B) Angiosperms

(C) Gymnosperms

(D) Bryophyta

Answer: (A) Pteridophyta

Explanation: Pteridophytes possess xylem and phloem, unlike bryophytes, but their flagellated male gametes generally swim through water to reach the archegonium. This limits fertilisation in dry conditions despite their developed conducting tissues.

161. Warm, moist conditions in a fungal culture most directly promote what process?

[RRB Group D 2025 recruitment, 04 Aug 2026 Shift 2]

(A) Spore germination and growth

(B) Formation of pigments only

(C) Storage of energy in vacuoles

(D) Maximal cell division irrespective of nutrients

Answer: (A) Spore germination and growth

Explanation: Many fungal spores germinate readily when moisture and suitable warmth are available. Water supports enzyme action and nutrient absorption, while temperature affects metabolic rates. Specific needs differ among species, so these conditions principally support development and colonisation.

160. Assertion: Binomial nomenclature standardises identification.
Reason: Each binomial has a generic name and a specific epithet.

Choose the correct relation.

[Bihar Police SI Mains Memory-Based Paper, 17 May 2026]

(A) Both are true and the reason explains the assertion

(B) Both true but the reason does not explain it

(C) Assertion true but reason false

(D) Assertion false but reason true

Answer: (A) Both are true and the reason explains the assertion

Explanation: The two-part scientific name specifies a genus and a species-level epithet, allowing unambiguous international communication. Its standardized structure explains why biological names remain consistent even when organisms possess numerous regional or common names.

159. For natural and artificial classification, which statements are correct:
I. artificial systems use few visible characters;
II. natural systems use many characters;
III. artificial classification best depicts phylogeny;
IV. natural systems are more stable?

[UP PGT Biology, 09 May 2026]

(A) I, II, III and IV

(B) II, III and IV only

(C) I and III only

(D) I, II and IV only

Answer: (D) I, II and IV only

Explanation: Artificial systems emphasise a limited selection of convenient characters and may bring unrelated groups together. Natural systems evaluate many anatomical and structural features, giving more defensible groupings. Their greater breadth makes statement III incorrect.

158. What is the defining characteristic of gymnosperms?

[NEET UG 2025, 04 May 2025]

(A) Seeds enclosed by fruit

(B) Naked seeds

(C) No seeds at all

(D) Reproduction by true flowers

Answer: (B) Naked seeds

Explanation: Gymnosperm literally means naked seed. Their ovules are not enclosed by an ovary and the resulting seeds remain exposed, commonly on cone scales. Angiosperms, by contrast, develop seeds within fruit-forming ovaries.

157. Which statement about bryophytes is incorrect?

[MPSC Group C Preliminary Examination, held 01 Jun 2025]

(A) They are called amphibians of the plant kingdom

(B) They require water for sexual reproduction

(C) They possess rhizoids instead of true roots

(D) Rhizopus is one of their examples

Answer: (D) Rhizopus is one of their examples

Explanation: Rhizopus is a fungus, not a bryophyte. Bryophytes such as liverworts and mosses lack true vascular roots and use rhizoids for anchorage. Their motile male gametes require water for fertilisation.

156. Which descending sequence correctly represents classification ranks in animals?

[UPSC CDS II, 14 September 2025, Q41]

(A) Class, Phylum, Order, Genus, Family, Species

(B) Phylum, Class, Family, Genus, Order, Species

(C) Order, Class, Phylum, Family, Species, Genus

(D) Phylum, Class, Order, Family, Genus, Species

Answer: (D) Phylum, Class, Order, Family, Genus, Species

Explanation: Animal classification becomes progressively more specific from phylum to class, order, family, genus and species. Each rank contains subdivisions at the next lower rank. Kingdom sits above phylum in the full hierarchy.

155. In which kingdom are organisms without a definite nucleus or membrane-bound organelles placed?

[SSC CGL Tier I, 12 Sep 2024 Shift 1]

(A) Fungi

(B) Protista

(C) Monera

(D) Plantae

Answer: (C) Monera

Explanation: Monera was the kingdom used in Whittaker’s system for prokaryotes, including bacteria and cyanobacteria. Their genetic material is not enclosed inside a nuclear membrane. Fungi, protists and plants are eukaryotic, possessing nuclei.

154. Choose the correct descending order of major plant taxonomic ranks.

[UPPSC PCS Prelims 2024 GS Paper I]

(A) Order, class, phylum, kingdom

(B) Class, kingdom, phylum, order

(C) Class, phylum, order, kingdom

(D) Kingdom, phylum, class, order

Answer: (D) Kingdom, phylum, class, order

Explanation: The broadest of the listed ranks is kingdom, followed by phylum or division, class and order. Each successive rank includes progressively closer relatives, and lower ranks continue through family, genus and species.

153. Which plant groups are examples of cryptogams?

[SSC MTS, 05 Nov 2024 Shift 1]

(A) Gymnosperms and angiosperms

(B) Pteridophytes and angiosperms

(C) Thallophytes and gymnosperms

(D) Bryophytes and thallophytes

Answer: (D) Bryophytes and thallophytes

Explanation: Cryptogams possess inconspicuous reproductive organs and propagate by spores rather than seeds. Traditional textbook groupings include thallophytes, bryophytes and pteridophytes. Gymnosperms and angiosperms are seed-bearing phanerogams.

152. Match Bryophyta, Pteridophyta, Gymnosperms and Angiosperms respectively

with moss, Selaginella, pine and rose.

[SSC MTS, 23 Oct 2024 Shift 3]

(A) Moss, rose, pine, Selaginella

(B) Moss, Selaginella, pine, rose

(C) Moss, Selaginella, rose, pine

(D) Pine, moss, rose, Selaginella

Answer: (B) Moss, Selaginella, pine, rose

Explanation: Mosses are bryophytes, Selaginella is a vascular spore-bearing lycophyte, pine has unenclosed gymnosperm seeds, and rose is a flowering angiosperm. Their sequence represents distinct stages of structural and reproductive complexity.

151. Which animal phylum is particularly characterised by a segmented body?

[SSC MTS, 08 Oct 2024 Shift 3]

(A) Chordata

(B) Arthropoda

(C) Annelida

(D) Mollusca

Answer: (C) Annelida

Explanation: Annelids such as earthworms and leeches display conspicuous repeated body segments, termed metameres. Arthropods are also segmented, but in this question the phylum identified with the typical segmented-worm body plan is Annelida.

150. What structures anchor bryophytes to their substrate?

[DSSSB Jail Warder, 18 Jun 2024 Shift 2]

(A) Rhizoids

(B) Leaves

(C) Trunk

(D) True roots

Answer: (A) Rhizoids

Explanation: Most bryophytes lack the differentiated vascular roots of higher plants. Instead, thread-like rhizoids fasten the gametophyte to soil, stone or bark. Water and nutrients can also be absorbed across exposed surfaces.

149. Which division is called the amphibians of the plant kingdom?

[Bombay High Court Peon, 08 Feb 2024 Shift 4]

(A) Bryophytes

(B) Thallophyta

(C) Gymnosperms

(D) Pteridophytes

Answer: (A) Bryophytes

Explanation: Bryophytes are terrestrial plants yet require external water for sexual fertilisation because their motile sperm must reach an egg. This dependence explains the amphibian analogy. Mosses and liverworts belong to the group.

148. What are nonvascular land plants traditionally called?

[CUET PG Life Sciences 2024]

(A) Pteridophytes

(B) Gymnosperms

(C) Angiosperms

(D) Bryophytes

Answer: (D) Bryophytes

Explanation: Bryophytes lack conducting tissues specialised as xylem and phloem. Their simple architecture limits height and favours moist environments. Ferns and seed plants are vascular, with tissue systems that move water and organic substances efficiently.

147. Which grouping correctly matches three gymnosperms?

[NEET UG 2024 Re-examination, 23 Jun 2024]

(A) Cedrus, Pinus and Sequoia

(B) Wolffia, Eucalyptus and Sequoia

(C) Polytrichum, Polysiphonia and Sphagnum

(D) Equisetum, Ginkgo and Adiantum

Answer: (A) Cedrus, Pinus and Sequoia

Explanation: Cedrus, Pinus and Sequoia are conifers that form naked seeds. Wolffia and Eucalyptus are flowering plants, Sphagnum is a bryophyte, Polysiphonia a red alga, and Adiantum and Equisetum are pteridophytes.

146. Which five kingdoms occur in Whittaker’s system?

[OSSSC Forest Guard, 24 Apr 2024 Shift 1]

(A) Monera, Protista, Fungi, Plantae, Animalia

(B) Viruses, lichens, fungi, plants, animals

(C) Virae, Protista, Fungi, Plantae, Animalia

(D) Bacterae, Protista, Fungi, Plantae, Animalia

Answer: (A) Monera, Protista, Fungi, Plantae, Animalia

Explanation: Whittaker separated prokaryotes, unicellular eukaryotes, fungi, plants and animals into five kingdoms. Viruses are acellular and are not counted among these cellular kingdoms. Lichens combine organisms from separate kingdoms.

145. Who proposed the five-kingdom scheme of classification in 1969?

[OSSSC Forest Guard, 05 May 2024 Shift 2]

(A) R. H. Whittaker

(B) David Philip

(C) William Harvey

(D) William Jones

Answer: (A) R. H. Whittaker

Explanation: Robert H. Whittaker proposed the influential five-kingdom framework in 1969. It considered cellular organisation, nutrition, reproduction and evolutionary relationships, separating fungi from plants and distinguishing prokaryotes from protists.

144. Which among bacteria, fungi, Paramecium and Chlamydomonas is generally NOT unicellular?

[RRB Technician Grade III, 30 Dec 2024 Shift 2]

(A) Bacteria

(B) Fungi

(C) Paramecium

(D) Chlamydomonas

Answer: (B) Fungi

Explanation: Fungi are generally multicellular and form hyphal networks, though yeast provides an important unicellular exception. Bacteria, Paramecium and Chlamydomonas are ordinarily single-celled organisms, making fungi the best general answer to the exam question.

143. Which description correctly identifies members of Platyhelminthes?

[SSC CGL Tier II, 02 March 2023]

(A) Triploblastic, bilaterally symmetrical and acoelomate

(B) Triploblastic, asymmetrical and acoelomate

(C) Diploblastic, bilateral and acoelomate

(D) Triploblastic, coelomate and asymmetrical

Answer: (A) Triploblastic, bilaterally symmetrical and acoelomate

Explanation: Flatworms possess three germ layers and bilateral symmetry, but they lack a true body cavity. This acoelomate organisation distinguishes them from pseudocoelomate nematodes and truly coelomate annelids, arthropods and chordates.

142. Identify the incorrect statement about Arthropoda.

[SSC CGL Tier I, 18 July 2023 Shift 4]

(A) Insecta is its largest class

(B) The exoskeleton is chiefly composed of lignin

(C) It includes an immense diversity of animal species

(D) Its members have jointed appendages

Answer: (B) The exoskeleton is chiefly composed of lignin

Explanation: Arthropods have a chitin-containing exoskeleton, not a lignin-based one. Lignin is a structural component of many plant cell walls. Jointed limbs and an extensive range of insect species are defining features of this animal phylum.

141. On which basis are Porifera commonly divided into classes?

[MP Police Constable, 24 August 2023]

(A) Nature of skeletal spicules

(B) Branching of appendages

(C) Mode of fertilisation alone

(D) Number of body segments

Answer: (A) Nature of skeletal spicules

Explanation: Sponges have internal supporting structures consisting of mineral spicules or spongin. Their composition and form provide key characters used to distinguish groups such as Calcarea, Hexactinellida and Demospongiae.

140. Which listed animal belongs to phylum Platyhelminthes?

[SSC CHSL, 20 March 2023]

(A) Sycon

(B) Leech

(C) Wuchereria

(D) Tapeworm

Answer: (D) Tapeworm

Explanation: Tapeworms are dorsoventrally flattened parasitic flatworms of phylum Platyhelminthes. Sycon is a sponge, leeches are segmented annelids, and Wuchereria is a filarial nematode. Their body plans reveal the underlying taxonomic distinctions.

139. In which animal phylum do ostia and osculum occur?

[CRPF Head Constable, 26 February 2023]

(A) Ctenophora

(B) Aschelminthes

(C) Porifera

(D) Annelida

Answer: (C) Porifera

Explanation: Sponges possess numerous tiny inlet pores called ostia and usually one or more larger outlet openings called oscula. Water enters through ostia, circulates through the canal system and exits through the osculum.

138. Which is not an arthropod?

[MP Police Constable, 29 August 2023]

(A) Octopus

(B) Scorpion

(C) Butterfly

(D) Locust

Answer: (A) Octopus

Explanation: Octopus is a cephalopod mollusc with a soft body and muscular arms. Scorpions, butterflies and locusts are arthropods, recognised by jointed appendages and an external cuticle containing chitin.

137. Which cells of sponges generally develop into gametes?

[MPSC Group B, 30 April 2023]

(A) Choanocytes

(B) Archaeocytes

(C) Myocytes

(D) Pinacocytes

Answer: (B) Archaeocytes

Explanation: Archaeocytes are mobile, undifferentiated sponge cells capable of differentiating into multiple cell types, including reproductive cells. Choanocytes primarily drive water currents and capture food, whereas pinacocytes cover external surfaces.

136. Which phylum ranks second after Arthropoda in number of described animal species?

[MP Police Constable, 31 August 2023]

(A) Locust

(B) Mollusca

(C) Prawn

(D) Annelida

Answer: (B) Mollusca

Explanation: Mollusca is widely described as the second-largest animal phylum after Arthropoda. It includes snails, clams, oysters, squids and octopuses, despite major differences in shell development and external appearance.

135. Which animal group commonly has an incomplete digestive tract?

[MP Patwari, 17 March 2023]

(A) Platyhelminthes

(B) Aschelminthes

(C) Porifera

(D) Echinodermata

Answer: (A) Platyhelminthes

Explanation: Many flatworms have a digestive cavity with one opening and therefore no separate anus. Tapeworms are an exception because they lack a digestive tract altogether. Nematodes have a complete alimentary canal.

134. A water vascular system is characteristic of which phylum?

[MP Forest Guard, 16 June 2023]

(A) Echinodermata

(B) Hemichordata

(C) Arthropoda

(D) Annelida

Answer: (A) Echinodermata

Explanation: Sea stars, sea urchins and related echinoderms use a hydraulic water vascular system. Its tube feet function in movement, food handling and gas exchange, making this structure highly distinctive in animal classification.

133. Which organism belongs to Coelenterata or Cnidaria?

[SSC Stenographer, 12 October 2023]

(A) Aurelia

(B) Spongilla

(C) Euspongia

(D) Sycon

Answer: (A) Aurelia

Explanation: Aurelia is a jellyfish placed within Cnidaria. The other three choices are sponges of Porifera. Cnidarians possess specialised stinging cells called cnidocytes, whereas sponges rely on a porous filtration system.

132. In which animal phylum is the body characteristically divided into head, thorax and abdomen?

[SSC CGL Tier I, 26 July 2023]

(A) Annelida

(B) Mollusca

(C) Arthropoda

(D) Chordata

Answer: (C) Arthropoda

Explanation: Many insects, members of Arthropoda, show three body regions: head, thorax and abdomen. This tagmosis accompanies a chitinous exoskeleton and jointed limbs. Other arthropods may display a cephalothorax and abdomen instead.

131. Which organism is an example of Aschelminthes or Nematoda?

[DDA Junior Engineer, 01 April 2023]

(A) Scorpion

(B) Cockroach

(C) Prawn

(D) Ascaris

Answer: (D) Ascaris

Explanation: Ascaris is a parasitic roundworm belonging to Nematoda, historically termed Aschelminthes. Its unsegmented cylindrical body has a pseudocoelom and complete digestive tract. The remaining organisms are arthropods.

130. Which specialised structures perform excretion in flatworms?

[SSC CGL Tier I, 18 July 2023]

(A) Nerve cells

(B) Flame cells

(C) Ganglia

(D) Hooks

Answer: (B) Flame cells

Explanation: Flatworms possess protonephridial systems whose terminal flame cells help regulate water and eliminate metabolic wastes. The beating cilia within these cells create fluid movement, an important characteristic of platyhelminth excretion.

129. Unsegmented, triploblastic, bilaterally symmetrical acoelomates are mainly classified under which phylum?

[SSC CGL Tier I, 24 July 2023]

(A) Cnidaria

(B) Ctenophora

(C) Platyhelminthes

(D) Porifera

Answer: (C) Platyhelminthes

Explanation: Platyhelminthes exhibit bilateral symmetry, three tissue layers and absence of a true body cavity. This combination differentiates flatworms from diploblastic cnidarians and ctenophores and from cellular-grade sponges.

128. What is generally considered the second-largest invertebrate phylum?

[MPSC Group B, 05 November 2023]

(A) Arthropoda

(B) Porifera

(C) Mollusca

(D) Echinodermata

Answer: (C) Mollusca

Explanation: Among invertebrates, molluscs form one of the most diverse phyla, surpassed in described species by arthropods. Mollusca includes gastropods, bivalves and cephalopods, which share variations of a mantle, visceral mass and muscular foot.

127. Which is a bryophyte?

[SSC CHSL, 15 March 2023]

(A) Cladophora

(B) Marsilea

(C) Marchantia

(D) A monocotyledon

Answer: (C) Marchantia

Explanation: Marchantia is a liverwort and therefore a bryophyte. Cladophora is a green alga; Marsilea is a fern ally belonging to pteridophytes. Bryophytes lack true vascular tissue and depend on water for fertilisation.

126. Which statement about bryophytes is incorrect?

[MP Patwari, 09 April 2023]

(A) They bear flowers

(B) Their spores are generally of one kind

(C) The principal plant body is haploid

(D) The gametophyte is dominant

Answer: (A) They bear flowers

Explanation: Bryophytes are flowerless plants that reproduce by spores. Their conspicuous green phase is the haploid gametophyte, while the sporophyte depends on it. Flowers evolved much later in seed-bearing angiosperms.

125. Moss and Marchantia are examples of which plant group?

[SSC GD Constable, 10 January 2023]

(A) Algae

(B) Gymnosperms

(C) Pteridophytes

(D) Bryophytes

Answer: (D) Bryophytes

Explanation: Mosses and liverworts, including Marchantia, are bryophytes. They reproduce by spores rather than seeds and have a dominant gametophyte. Their sperm require a film of water to reach the egg.

124. Conifers are placed in which group of plants?

[BPSC 67th Preliminary Examination, 30 September 2022]

(A) Gymnosperms

(B) Monocotyledons

(C) Dicotyledons

(D) Angiosperms

Answer: (A) Gymnosperms

Explanation: Conifers such as pine and fir bear naked seeds associated with cones and therefore belong to gymnosperms. Monocotyledons and dicotyledons are traditionally distinguished groups within flowering angiosperms.

123. Who popularised binomial nomenclature for scientific naming?

[RRB NTPC CBT 2, 15 June 2022]

(A) Claude Louis Berthollet

(B) Dmitri Mendeleev

(C) Carolus Linnaeus

(D) John Dalton

Answer: (C) Carolus Linnaeus

Explanation: Carolus Linnaeus standardised the two-part scientific naming system using genus and specific epithet. A consistent Latinised binomial allows organisms to be identified internationally despite differences in regional common names.

122. Which of the following categories does not include human beings?

[SSC MTS, 07 July 2022]

(A) Chordata

(B) Porifera

(C) Hominidae

(D) Vertebrata

Answer: (B) Porifera

Explanation: Humans belong to Chordata, Vertebrata and the family Hominidae. Porifera consists of simple aquatic sponges lacking true tissues and organ systems, so humans cannot be included in that phylum.

121. Which pair of plant groups possesses vascular tissues?

[NVS Trained Graduate Teacher, 29 November 2022]

(A) Bryophyta and Thallophyta

(B) Gymnosperms and Pteridophyta

(C) Bryophyta, Gymnosperms and Pteridophyta

(D) Gymnosperms, Pteridophyta and Thallophyta

Answer: (B) Gymnosperms and Pteridophyta

Explanation: Pteridophytes and gymnosperms have differentiated xylem and phloem for internal transport. Bryophytes are nonvascular, and traditional thallophyte groups such as algae lack the typical vascular system of land plants.

120. In which group are ovules not enclosed inside an ovary?

[SSC Stenographer, 17 November 2022]

(A) Pteridophytes

(B) Gymnosperms

(C) Algae

(D) Angiosperms

Answer: (B) Gymnosperms

Explanation: Gymnosperms bear naked ovules and seeds, typically on cones rather than enclosed inside ovaries. Angiosperms produce flowers with ovaries that mature into fruits. Ferns and algae do not form seeds at all.

119. The central cavity of sponges is commonly lined by which flagellated cells?

[SSC CGL, 09 December 2022]

(A) Somatic cells

(B) Collar cells

(C) White cells

(D) Sex cells

Answer: (B) Collar cells

Explanation: Choanocytes, also called collar cells, use flagella to generate water currents through sponges. Their collars trap suspended food particles. The central spongocoel is lined by choanocytes in the simple asconoid canal arrangement.

118. Animals with numerous small pores through which water circulates are placed in which phylum?

[SSC CPO, 11 November 2022]

(A) Porifera

(B) Ctenophora

(C) Platyhelminthes

(D) Annelida

Answer: (A) Porifera

Explanation: Porifera literally means pore-bearing. Water enters a sponge through ostia and leaves by an osculum, enabling filter feeding and gas exchange. Sponges lack the well-developed organ systems found in many other animal phyla.

117. Soft-bodied animals usually possessing a mantle and muscular foot belong to which phylum?

[NVS Junior Secretariat Assistant, 09 March 2022]

(A) Echinodermata

(B) Annelida

(C) Mollusca

(D) Porifera

Answer: (C) Mollusca

Explanation: A mantle, visceral mass and muscular foot characterise the basic molluscan body plan. The mantle often secretes a calcareous shell. Snails, mussels and octopuses illustrate variations within the phylum.

116. Cycads, conifers and Ginkgo are representatives of which plant group?

[SSC CPO, 09 November 2022]

(A) Gymnosperms

(B) Angiosperms

(C) Pteridophytes

(D) Bryophytes

Answer: (A) Gymnosperms

Explanation: Cycads, Ginkgo and conifers produce seeds without enclosing them in fruits. Their naked-seeded condition places them among gymnosperms, unlike flowering plants whose ovules are enclosed by an ovary.

115. To which vertebrate class does a crocodile belong?

[REET, 23 July 2022]

(A) Aves

(B) Reptilia

(C) Amphibia

(D) Pisces

Answer: (B) Reptilia

Explanation: Crocodiles belong to Reptilia. They breathe through lungs, possess keratinised scales and lay shelled eggs on land. Despite their four-chambered heart, they are reptiles rather than birds or mammals.

114. Which division is popularly known as the amphibians of the plant kingdom?

[SSC MTS, 12 July 2022]

(A) Pteridophyta

(B) Thallophyta

(C) Angiosperms

(D) Bryophyta

Answer: (D) Bryophyta

Explanation: Bryophytes live primarily on land but require free water for the motile male gametes to reach the egg. This dependence on water for sexual reproduction explains the familiar analogy with amphibians.

113. Which of the listed plant groups is seed-bearing?

[SSC MTS, 21 July 2022]

(A) Thallophyta

(B) Pteridophyta

(C) Bryophyta

(D) Gymnosperms

Answer: (D) Gymnosperms

Explanation: Gymnosperms reproduce using seeds, commonly held on reproductive cones. Algae, bryophytes and pteridophytes generally disperse by spores and do not produce seeds. Seed formation represents an important evolutionary advance.

112. Which listed group does NOT belong to non-chordates?

[SSC CGL, 03 December 2022]

(A) Reptiles

(B) Arthropods

(C) Porifera

(D) Arachnids

Answer: (A) Reptiles

Explanation: Reptiles are vertebrates belonging to Chordata because they possess a notochord during development and a dorsal hollow nerve cord. Arthropods, arachnids and sponges are all non-chordate animals.

111. Assess these statements:
I. Angiosperm seeds develop enclosed within a fruit.
II. Bryophytes are called amphibians of the plant kingdom.

[DSSSB Primary Teacher, 07 March 2022]

(A) Neither statement is correct

(B) Both statements are correct

(C) Only statement II is correct

(D) Only statement I is correct

Answer: (B) Both statements are correct

Explanation: In flowering plants the mature ovary develops into a fruit that encloses the seeds. Bryophytes require water for fertilisation even though they grow terrestrially. Thus both assertions accurately describe their respective plant groups.

110. Bacteria are classified in which kingdom of Whittaker’s system?

[SSC Selection Post, 15 March 2022]

(A) Fungi

(B) Monera

(C) Plantae

(D) Protista

Answer: (B) Monera

Explanation: Kingdom Monera encompasses prokaryotic life forms such as bacteria and cyanobacteria in the classical five-kingdom system. They lack membrane-bound nuclei and organelles, unlike the eukaryotic groups Protista, Fungi and Plantae.

109. Which structure gives a plant cell its rigid external boundary?

[SSC CHSL, 27 May 2022]

(A) Cell membrane

(B) Plastids

(C) Cell wall

(D) Vacuole

Answer: (C) Cell wall

Explanation: The plant cell wall is a rigid extracellular layer composed largely of cellulose. Its support and shape contrast with the flexible plasma membrane. Cell-wall composition is also a useful clue in distinguishing plant, fungal and bacterial groups.

108. Animals with jointed legs are generally classified under which phylum?

[RRB NTPC, 27 February 2021]

(A) Arthropoda

(B) Echinodermata

(C) Annelida

(D) Nematoda

Answer: (A) Arthropoda

Explanation: The name Arthropoda refers to jointed feet. Members include insects, spiders, crustaceans and centipedes. A chitinous external skeleton and paired articulated appendages are characteristic of this diverse phylum.

107. Which animal does not belong to Mollusca?

[RRB NTPC, 23 July 2021]

(A) Unio

(B) Scolopendra

(C) Octopus

(D) Snail

Answer: (B) Scolopendra

Explanation: Scolopendra is a centipede belonging to phylum Arthropoda. Unio is a freshwater bivalve, and octopus and snail are other molluscan examples. Jointed legs distinguish centipedes from soft-bodied molluscs.

106. Which phylum comprises exclusively free-living marine animals?

[RRB NTPC, 03 April 2021]

(A) Mollusca

(B) Nematoda

(C) Arthropoda

(D) Echinodermata

Answer: (D) Echinodermata

Explanation: Echinoderms such as starfish, sea cucumbers and sea urchins are exclusively marine and generally free-living. They have a distinctive water vascular system and frequently display pentaradial symmetry as adults.

105. Which plants produce seeds enclosed by fruits?

[RRB NTPC, 04 February 2021]

(A) Gymnosperms

(B) Pteridophytes

(C) Angiosperms

(D) Bryophytes

Answer: (C) Angiosperms

Explanation: Angiosperms are flowering seed plants whose ovaries mature into fruits surrounding the seeds. Gymnosperms have naked seeds; pteridophytes and bryophytes reproduce with spores and do not form fruits.

104. Which set correctly lists the five kingdoms in Whittaker’s classification?

[MPSC Subordinate Services Prelims 2020, held 04 September 2021]

(A) Protista, Fungi, Mammalia, Annelida, Plantae

(B) Monera, Protista, Fungi, Plantae, Animalia

(C) Protista, Fungi, Plantae, Porifera, Animalia

(D) Monera, Fungi, Mammalia, Plantae, Animalia

Answer: (B) Monera, Protista, Fungi, Plantae, Animalia

Explanation: Robert Whittaker recognised Monera, Protista, Fungi, Plantae and Animalia as the five kingdoms. Mammalia and Annelida represent subdivisions of animals rather than separate kingdoms. This system highlighted fundamental differences in cell organisation and nutrition.

103. Which term describes fusion of cytoplasm between two fungal gametes or cells?

[NEET UG, 2021]

(A) Karyogamy

(B) Plasmogamy

(C) Saprophytism

(D) Heterocyst formation

Answer: (B) Plasmogamy

Explanation: Plasmogamy is fusion of cytoplasmic material during fungal sexual reproduction. Karyogamy denotes nuclear fusion, which may occur considerably later. Some fungi therefore retain a dikaryotic stage with two genetically distinct nuclei.

102. Which group is not included under the kingdom Animalia in the five-kingdom scheme?

[RRB NTPC, 30 December 2020]

(A) Metazoa

(B) Protozoa

(C) Choanozoa

(D) Bilateria

Answer: (B) Protozoa

Explanation: Protozoans such as Amoeba and Paramecium are placed in Protista under Whittaker’s traditional framework. Metazoa comprises multicellular animals, whereas modern classifications may treat choanoflagellate relatives separately; this exam follows the textbook five-kingdom approach.

101. Which description correctly applies to viroids?

[NEET UG, 2020]

(A) RNA enclosed in a protein capsid

(B) Free infectious RNA lacking a protein coat

(C) Protein-coated DNA

(D) Free infectious DNA

Answer: (B) Free infectious RNA lacking a protein coat

Explanation: Viroids consist of small circular infectious RNA molecules without any protein capsid. They differ from viruses in structure and size. T. O. Diener discovered them while investigating potato spindle tuber disease.

100. Metameric segmentation occurs in which pair of animal phyla?

[RPSC Senior Teacher Science, 04 July 2019]

(A) Annelida and Arthropoda

(B) Echinodermata and Arthropoda

(C) Annelida and Chordata

(D) Platyhelminthes and Arthropoda

Answer: (A) Annelida and Arthropoda

Explanation: Metamerism refers to serial repetition of body segments. It is especially clear in annelids and many arthropods, although arthropod segments may fuse into functional regions. This repeated architecture helps identify their organisation.

99. Who proposed the five-kingdom classification of organisms?

[SSC Stenographer, 07 February 2019]

(A) R. H. Whittaker

(B) A. Williamson

(C) A. Fleming

(D) L. Lawrence

Answer: (A) R. H. Whittaker

Explanation: Robert Whittaker proposed the five-kingdom scheme in 1969, distinguishing Monera, Protista, Fungi, Plantae and Animalia. The framework uses cellular structure, level of organisation, mode of nutrition and reproductive and evolutionary features.

98. Which scientist introduced the five-kingdom classification system?

[SSC CPO, 12 March 2019]

(A) William Paley

(B) Charles Darwin

(C) Carl Woese

(D) Robert Whittaker

Answer: (D) Robert Whittaker

Explanation: Whittaker’s five-kingdom model recognised fungi as a distinct kingdom rather than grouping them with green plants. Carl Woese later proposed the three-domain system using molecular evidence, a different classification scheme.

97. Who is called the father of modern taxonomy?

[MP Pre-Nursing Selection Test, 07 July 2019]

(A) Carolus Linnaeus

(B) Hugh Strickland

(C) Thomas Huxley

(D) Charles Darwin

Answer: (A) Carolus Linnaeus

Explanation: Linnaeus systematised hierarchical classification and standardised two-word species names. His publications helped establish modern taxonomic conventions, although molecular phylogenetics has subsequently refined many relationships among organisms.

96. Which factors are considered in Whittaker’s five-kingdom classification?

[RPSC Senior Teacher Science, 18 February 2019]

(A) Only cell type and tissue level

(B) Only nutrition and reproduction

(C) Cell structure, organisation, reproduction and nutrition

(D) Only cell structure and nutrition

Answer: (C) Cell structure, organisation, reproduction and nutrition

Explanation: Whittaker considered cell structure, body organisation, nutrition, reproduction and inferred phylogenetic relationships. Applying multiple criteria allowed fungi to be separated from plants and prokaryotes from unicellular eukaryotes.

95. Which statement is false about infectious agents?

[NEET UG, 2019]

(A) Viroids have no protein shell

(B) Viruses are obligate intracellular parasites

(C) The viral protein coat alone is the infectious genetic material

(D) Prions consist of misfolded proteins

Answer: (C) The viral protein coat alone is the infectious genetic material

Explanation: Viral genetic information resides in DNA or RNA, not in its protective capsid. Prions are infectious proteins, while viroids are infectious RNA without a coat. These differences separate the three classes of acellular agents.

94. Which statement about fungi is incorrect?

[NEET UG, 2019]

(A) Morels and truffles are edible ascomycetes

(B) Claviceps produces ergot alkaloids

(C) Conidia form externally while ascospores form inside asci

(D) Yeasts ordinarily have long multicellular hyphae

Answer: (D) Yeasts ordinarily have long multicellular hyphae

Explanation: Yeasts such as Saccharomyces are typically unicellular rather than long, filamentous fungi. Morels and truffles are prized edible fungi, while Claviceps produces alkaloids. Conidia and ascospores differ in their formation and reproductive roles.

93. Select the correct matching: saprophyte, parasite, lichen and mycorrhiza.

[NEET UG, 2019]

(A) Saprophyte-root symbiosis; parasite-decomposer; lichen-parasitic; mycorrhiza-alga-fungus

(B) Saprophyte-parasite; parasite-decomposer; lichen-root symbiosis; mycorrhiza-alga-fungus

(C) Saprophyte-decomposer; parasite-root symbiosis; lichen-parasite; mycorrhiza-alga-fungus

(D) Saprophyte-decomposer; parasite-on living host; lichen-alga and fungus; mycorrhiza-fungus and root

Answer: (D) Saprophyte-decomposer; parasite-on living host; lichen-alga and fungus; mycorrhiza-fungus and root

Explanation: Saprophytes use dead organic substrates and parasites draw nutrients from living hosts. A lichen pairs photosynthetic organisms with fungi, while mycorrhiza is an association between fungal hyphae and plant roots.

92. Algae were placed mainly in which traditional plant division?

[RRB Group D, 23 September 2018]

(A) Bryophyta

(B) Thallophyta

(C) Gymnosperms

(D) Pteridophyta

Answer: (B) Thallophyta

Explanation: Thallophyta was traditionally used for organisms with an undifferentiated thallus, including many algae. Modern classification places algae in multiple evolutionary lineages, so the textbook division is primarily a historical examination category.

91. Which descending taxonomic sequence is correctly arranged?

[UPSC NDA I, 22 April 2018, General Ability]

(A) Phylum, Class, Order, Family, Genus

(B) Phylum, Class, Family, Order, Genus

(C) Family, Order, Class, Species, Genus

(D) Class, Family, Order, Species, Genus

Answer: (A) Phylum, Class, Order, Family, Genus

Explanation: Phylum includes multiple classes, each class contains orders, each order contains families, and each family contains genera. Species follow genus as the narrowest standard rank. The other sequences reverse one or more levels.

90. Which substance commonly forms fungal cell walls?

[RRB Group D, 28 September 2018 Shift 1]

(A) Chitin

(B) Lignin

(C) Pectin

(D) Cellulose

Answer: (A) Chitin

Explanation: Chitin is a nitrogen-containing polysaccharide important in the walls of true fungi. Pectin, cellulose and lignin are common plant structural materials. Cell wall composition is therefore one classification clue.

89. Which plant group possesses specialised vessels for conducting water?

[RRB Group D, 28 September 2018 Shift 2]

(A) Fungi

(B) Angiosperms

(C) Bryophyta

(D) Thallophyta

Answer: (B) Angiosperms

Explanation: Angiosperms typically possess xylem vessels that transport water and minerals. Bryophytes lack true vascular tissue, and fungi do not have plant-style xylem. The question contrasts advanced vascular plants with simpler groups.

88. Which organism reproduces through spore formation?

[RRB Group D, 16 October 2018]

(A) Planaria

(B) Bryophyllum

(C) Hydra

(D) Rhizopus

Answer: (D) Rhizopus

Explanation: Rhizopus, a bread mould, produces spores in sporangia on specialised hyphae. Hydra buds, planarians may reproduce through fission and regeneration, while Bryophyllum can form plantlets on leaf margins.

87. Which statement on the traditional classification of plants is correct?

[UPSC NDA I, 22 April 2018, General Ability]

(A) Thallophytes possess fully differentiated plant bodies

(B) Funaria is a fungus

(C) All pteridophytes are phanerogams

(D) Bryophytes do not have a true vascular conducting system

Answer: (D) Bryophytes do not have a true vascular conducting system

Explanation: Bryophytes have no true xylem or phloem and therefore are nonvascular. Funaria is a moss, thallophytes lack differentiated organs, and pteridophytes reproduce by spores rather than seeds, so they are cryptogams.

86. Which of the following is a cnidarian?

[RRB Group D, 18 September 2018]

(A) Hydra

(B) Plasmodium

(C) Planaria

(D) Yeast

Answer: (A) Hydra

Explanation: Hydra is a freshwater cnidarian bearing stinging cnidocytes on its tentacles. Planaria is a flatworm, Plasmodium a parasitic protist, and yeast a fungus. Their distinct cellular organisation determines their kingdoms and phyla.

85. Organisms without a true membrane-bound nucleus belong chiefly to which kingdom?

[RRB Group D, 22 September 2018]

(A) Protista

(B) Fungi

(C) Monera

(D) Plantae

Answer: (C) Monera

Explanation: Kingdom Monera contains prokaryotes such as bacteria and cyanobacteria. Their genetic material is not enclosed by a nuclear membrane. The other choices contain organisms with eukaryotic cellular organisation.

84. Which among these organisms is NOT a prokaryote?

[NEET UG, 2018]

(A) Nostoc

(B) Mycobacterium

(C) Saccharomyces

(D) Oscillatoria

Answer: (C) Saccharomyces

Explanation: Saccharomyces is a yeast and therefore a eukaryotic fungus with a membrane-bound nucleus. Nostoc and Oscillatoria are cyanobacteria, whereas Mycobacterium is a bacterium. All three are prokaryotes.

83. Which assertion is wrong?

[NEET UG, 2018]

(A) Sporozoans use pseudopodia for obtaining food and moving

(B) Mushrooms are basidiomycetes

(C) Cell walls are common in Plantae and Fungi

(D) Monerans lack mitochondria

Answer: (A) Sporozoans use pseudopodia for obtaining food and moving

Explanation: Sporozoans such as Plasmodium generally lack locomotory organelles in the stages described by traditional classification. Pseudopodia characterise amoeboid protozoans. Mushrooms are basidiomycetes, and monerans are prokaryotes lacking mitochondria.

82. Which fungus produces spores externally on basidia following meiosis?

[NEET UG, 2018]

(A) Agaricus

(B) Alternaria

(C) Neurospora

(D) Saccharomyces

Answer: (A) Agaricus

Explanation: Agaricus is a basidiomycete; basidiospores form externally upon basidia after meiosis. By contrast, Neurospora and Saccharomyces produce sexual spores within asci. Alternaria was traditionally classified among imperfect fungi.

81. A characteristic distinguishing ciliate protozoans is:

[NEET UG, 2018]

(A) Pseudopodia for capturing prey

(B) Possession of contractile vacuoles only

(C) Flagella as the chief locomotory structure

(D) Two different nuclear types

Answer: (D) Two different nuclear types

Explanation: Ciliates often possess both a macronucleus for everyday functions and micronuclei involved in sexual reproduction. Other protists may have contractile vacuoles, but this nuclear dimorphism is characteristic of ciliates.

80. Which microorganisms are often termed the chief producers in oceans?

[NEET UG, 2018]

(A) Cyanobacteria

(B) Diatoms

(C) Dinoflagellates

(D) Euglenoids

Answer: (B) Diatoms

Explanation: Diatoms are photosynthetic chrysophytes widely present in marine plankton. Their abundant primary production supports ocean food webs. They possess siliceous cell coverings known as frustules that can accumulate as diatomaceous earth.

79. Which groups can thrive in extremely saline conditions?

[NEET UG, 07 May 2017]

(A) Archaebacteria

(B) Eubacteria

(C) Cyanobacteria

(D) Mycobacteria

Answer: (A) Archaebacteria

Explanation: Halophilic archaea possess distinctive molecular adaptations to concentrated salt solutions. Their protein and membrane systems allow growth where most familiar organisms cannot survive, illustrating physiological diversity within Archaea.

78. Who suggested a five-kingdom classification of living organisms?

[SSC CGL Tier I, 08 August 2017]

(A) Ernst Mayr

(B) R. H. Whittaker

(C) Martinus Beijerinck

(D) Dmitri Ivanovsky

Answer: (B) R. H. Whittaker

Explanation: Whittaker proposed five kingdoms in 1969, separating prokaryotes, unicellular eukaryotes, fungi, plants and animals. This replaced some shortcomings of earlier two- and three-kingdom schemes.

77. Which criteria did Whittaker use in creating the five-kingdom system?

[RPSC Second Grade Science, 01 July 2017]

(A) Mode of nutrition only

(B) Mode of reproduction only

(C) Cellular structure only

(D) All of these criteria

Answer: (D) All of these criteria

Explanation: Whittaker combined nutrition, cellular organisation, reproduction and other evidence in his classification. Using a single trait would mix organisms with fundamentally different cell types or nutritional strategies.

76. How do viroids differ structurally from typical viruses?

[NEET UG, 2017]

(A) DNA plus protein

(B) Naked DNA

(C) RNA plus a protein coat

(D) RNA without a protein coat

Answer: (D) RNA without a protein coat

Explanation: A viroid is a minute infectious RNA molecule lacking the protein capsid found in viruses. Viroids cause certain plant diseases and rely entirely on host-cell mechanisms for multiplication.

75. Which statement is not correct for kingdom Monera?

[NEET UG Gujarati Paper, 2017]

(A) Its members existed very early in Earth’s history

(B) Its cellular organisation is prokaryotic

(C) Autotrophic and heterotrophic modes both occur

(D) Cell division occurs by typical mitosis

Answer: (D) Cell division occurs by typical mitosis

Explanation: Monerans do not have membrane-enclosed nuclei or a mitotic spindle. Most multiply by binary fission rather than eukaryotic mitosis. The kingdom includes autotrophic cyanobacteria and many heterotrophic bacteria.

74. Which genus is a sac fungus?

[NEET UG Gujarati Paper, 2017]

(A) Agaricus

(B) Neurospora

(C) Mucor

(D) Albugo

Answer: (B) Neurospora

Explanation: Neurospora is an ascomycete whose sexual spores develop in asci. Agaricus produces basidiospores and belongs to Basidiomycetes. Mucor and Albugo were classed with lower fungi in older textbooks.

73. Which is a flagellated protozoan?

[NEET UG Gujarati Paper, 2017]

(A) Paramecium

(B) Trypanosoma

(C) Entamoeba

(D) Plasmodium

Answer: (B) Trypanosoma

Explanation: Trypanosoma is a flagellated parasitic protist transmitted by insect vectors. Paramecium is a ciliate, Entamoeba uses pseudopodia, and Plasmodium is traditionally regarded as a sporozoan.

72. The protein covering of a virus is termed:

[NEET UG Gujarati Paper, 2017]

(A) Core

(B) Capsid

(C) Trichome

(D) Capsule

Answer: (B) Capsid

Explanation: The viral capsid is built from protein subunits called capsomeres and protects the nucleic acid. A bacterial capsule is an external protective layer, while a trichome refers to certain cellular hairs or filaments.

71. Which of these animals is a mollusc?

[RRB NTPC, 18 April 2016]

(A) Snail

(B) Starfish

(C) Earthworm

(D) Cockroach

Answer: (A) Snail

Explanation: Snails possess the soft body, mantle and muscular foot typical of Mollusca. Starfish belong to Echinodermata, earthworms to Annelida and cockroaches to Arthropoda, demonstrating differences between the major invertebrate phyla.

70. Which assertion is incorrect regarding true fungi?

[NEET UG Phase II, 2016]

(A) They are eukaryotes

(B) Every species has walls made exclusively from cellulose

(C) They are heterotrophs

(D) Both unicellular and multicellular forms occur

Answer: (B) Every species has walls made exclusively from cellulose

Explanation: True fungal walls normally contain chitin and glucans, not purely cellulose. Fungi are eukaryotic absorptive heterotrophs, comprising yeasts and filamentous species. Their wall composition helps distinguish them from plants.

69. Methanogens are members of which group?

[NEET UG Phase II, 2016]

(A) Eubacteria

(B) Archaebacteria

(C) Dinoflagellates

(D) Slime moulds

Answer: (B) Archaebacteria

Explanation: Methanogens are methane-producing archaea occurring in anaerobic habitats such as wetlands, sewage digesters and ruminant stomachs. Their distinctive biochemistry and cell envelopes distinguish them from eubacteria.

68. Choose the false statement concerning diatoms.

[NEET UG Phase II, 2016]

(A) Their silica-based cell walls disintegrate very easily

(B) Their skeletal remains form diatomaceous earth

(C) They contribute greatly to marine photosynthesis

(D) Many live as microscopic plankton

Answer: (A) Their silica-based cell walls disintegrate very easily

Explanation: Diatom frustules contain silica and resist decay remarkably well. Huge accumulations of these shells form diatomaceous earth. Diatoms are floating photosynthetic protists and constitute an important component of marine primary productivity.

67. Which property attributed to viroids is incorrect?

[NEET UG Phase I, 2016]

(A) They have no protein coat

(B) They are smaller than most viruses

(C) They cause infections

(D) They contain high-molecular-weight RNA

Answer: (D) They contain high-molecular-weight RNA

Explanation: Viroids are small, low-molecular-weight RNA agents capable of infecting plants. They possess neither a capsid nor DNA. Their simple structure contrasts sharply with the more elaborate particles formed by viruses.

66. Which taxonomic hierarchy is correctly written from highest to lowest?

[UPSC CAPF Assistant Commandant, 26 June 2016]

(A) Kingdom, Phylum, Order, Genus, Family, Class, Species

(B) Kingdom, Order, Class, Phylum, Family, Genus, Species

(C) Kingdom, Class, Order, Phylum, Family, Species, Genus

(D) Kingdom, Phylum, Class, Order, Family, Genus, Species

Answer: (D) Kingdom, Phylum, Class, Order, Family, Genus, Species

Explanation: The standard progression from broadest to narrowest is kingdom, phylum, class, order, family, genus and species. Related species form genera and related genera form families. Scientific classification employs this nested hierarchy.

65. Chrysophytes, dinoflagellates, euglenoids and slime moulds belong to which traditional kingdom?

[NEET UG Phase I, 2016]

(A) Monera

(B) Protista

(C) Fungi

(D) Animalia

Answer: (B) Protista

Explanation: Whittaker grouped many eukaryotic microorganisms within Protista. Chrysophytes, euglenoids, dinoflagellates and slime moulds show considerable ecological and nutritional diversity but differ from prokaryotic Monera.

64. Which kingdom principally includes unicellular eukaryotic organisms?

[RPSC Examination, 2015]

(A) Monera

(B) Protista

(C) Fungi

(D) All three kingdoms

Answer: (B) Protista

Explanation: Protista contains many single-celled eukaryotes, including protozoans and numerous unicellular algae. Monera comprises prokaryotes, while most fungi are filamentous multicellular organisms, with yeast as an exception.

63. Which pairing of an organism with its fungal classification is correct?

[AIPMT, 2015]

(A) Agaricus-parasitic basidiomycete

(B) Phytophthora-basidiomycete

(C) Alternaria-Deuteromycetes with no known sexual stage

(D) Mucor-Ascomycetes reproducing by conjugation

Answer: (C) Alternaria-Deuteromycetes with no known sexual stage

Explanation: Alternaria was traditionally placed in Deuteromycetes because its sexual stage was not identified. Agaricus is chiefly a saprophytic basidiomycete, while Phytophthora and Mucor belong to different fungus-like or fungal groups.

62. A true membrane-enclosed nucleus is missing in which organism?

[AIPMT, 2015]

(A) Volvox

(B) Anabaena

(C) Mucor

(D) Vaucheria

Answer: (B) Anabaena

Explanation: Anabaena is a filamentous cyanobacterium and therefore prokaryotic. It lacks a nuclear membrane. Volvox and Vaucheria are eukaryotic algae, whereas Mucor is a eukaryotic fungus.

61. Which virus has helical RNA encased in regularly arranged capsomeres?

[AIPMT, 2014]

(A) Tobacco mosaic virus

(B) Measles virus

(C) Retrovirus

(D) Poliovirus

Answer: (A) Tobacco mosaic virus

Explanation: Tobacco mosaic virus has a classic rod-shaped helical capsid surrounding a single-stranded RNA genome. Its uniform capsomeres make it a standard example of helical viral symmetry in biology textbooks.

60. Match the following organisms with their groups: A Ascaris, B malarial parasite, C housefly, D cow; 1 Mammalia, 2 Arthropoda, 3 Nematoda, 4 Protozoa.

[UPSC CDS II, 2014]

(A) A-3, B-4, C-2, D-1

(B) A-3, B-2, C-4, D-1

(C) A-1, B-2, C-4, D-3

(D) A-1, B-4, C-2, D-3

Answer: (A) A-3, B-4, C-2, D-1

Explanation: Ascaris is a nematode roundworm, the malarial parasite Plasmodium is a protozoan protist, the housefly is an arthropod insect, and the cow is a mammal. Hence the matching is 3, 4, 2, 1.

59. Which structure chiefly differentiates archaebacteria from eubacteria?

[AIPMT, 2014]

(A) General nutritional mode

(B) Cell shape

(C) Ordinary division method

(D) Membrane lipid structure

Answer: (D) Membrane lipid structure

Explanation: Archaea have characteristic membrane lipids with ether linkages and branched hydrocarbon chains. Bacteria generally use ester-linked fatty acids. These molecular differences help archaea survive in specialised and sometimes extreme habitats.

58. Which statement about gametes is incorrect?

[NEET UG, 2013]

(A) Isogametes are similar

(B) Anisogametes differ in one or more traits

(C) In oomycetes the female gamete is small and motile while the male is large

(D) Chlamydomonas may show isogamy or anisogamy

Answer: (C) In oomycetes the female gamete is small and motile while the male is large

Explanation: Oogamous reproduction typically has a large non-motile female gamete and a smaller male gamete. The reversed description in the stated option is therefore false. Chlamydomonas displays diverse forms of sexual reproduction.

57. Pigment-bearing membranous extensions in certain cyanobacteria are called:

[NEET UG, 2013]

(A) Heterocysts

(B) Basal bodies

(C) Pneumatophores

(D) Chromatophores

Answer: (D) Chromatophores

Explanation: Chromatophores are membrane-associated structures containing photosynthetic pigments in older descriptions of bacteria and cyanobacteria. Heterocysts specialise in nitrogen fixation, while basal bodies and pneumatophores serve entirely different functions.

56. Which group is especially likely to inhabit extreme deep-sea environments?

[NEET UG, 2013]

(A) Archaebacteria

(B) Ordinary surface-water bacteria

(C) Blue-green algae

(D) Terrestrial saprophytic fungi

Answer: (A) Archaebacteria

Explanation: Many archaea possess metabolic and structural adaptations for high pressure, unusual temperatures or oxygen-poor deep-sea sediments. Photosynthetic cyanobacteria require light, making them less characteristic of great ocean depths.

55. How many are autotrophs: Lactobacillus, Nostoc, Chara, Nitrosomonas, Nitrobacter, Streptomyces, Saccharomyces, Trypanosoma, Porphyra and Wolffia?

[AIPMT Mains, 2012]

(A) Four

(B) Five

(C) Six

(D) Three

Answer: (C) Six

Explanation: Nostoc, Chara, Porphyra and Wolffia are photosynthetic, while Nitrosomonas and Nitrobacter are chemoautotrophic bacteria. The remaining four depend on organic food. The total number of autotrophs is therefore six.

54. Which grouping correctly singles out an organism that differs taxonomically from the others?

[AIPMT Mains, 2012]

(A) UAA, UAG, UGA as stop codons, excluding UAG

(B) Kangaroo, koala, wombat as marsupials, excluding wombat

(C) Plasmodium, Cuscuta, Trypanosoma as protozoan parasites, excluding Cuscuta

(D) Typhoid, pneumonia, diphtheria as bacterial diseases, excluding diphtheria

Answer: (C) Plasmodium, Cuscuta, Trypanosoma as protozoan parasites, excluding Cuscuta

Explanation: Cuscuta is a parasitic flowering plant, whereas Plasmodium and Trypanosoma are unicellular parasitic protists. UAG is a stop codon and wombats are marsupials, so the proposed exceptions in those groups fail.

53. Which kingdom displays the widest variety of nutritional strategies?

[AIPMT Prelims, 2012]

(A) Plantae

(B) Fungi

(C) Animalia

(D) Monera

Answer: (D) Monera

Explanation: Bacteria possess remarkable metabolic diversity: photosynthesis, chemosynthesis, fermentation, saprotrophy and parasitism all occur. This breadth surpasses the predominantly photosynthetic plants and chiefly heterotrophic fungi and animals.

52. Useful microorganisms responsible for curd making and many antibiotics are largely classified as:

[AIPMT Prelims, 2012]

(A) Heterotrophic bacteria

(B) Cyanobacteria

(C) Archaebacteria

(D) Chemosynthetic autotrophs

Answer: (A) Heterotrophic bacteria

Explanation: Lactobacillus uses organic substrates to ferment milk into curd, while Streptomyces produces numerous antibiotics. Both are heterotrophic bacteria. They differ from cyanobacteria and chemoautotrophs that make food using light or inorganic chemical energy.

51. Which taxonomic assignment is correct?

[AIPMT Prelims, 2012]

(A) Nostoc and Anabaena are protists

(B) Paramecium and Penicillium belong to the same kingdom

(C) Lichen consists of algae and protozoa

(D) Bread-making yeast is a fungus

Answer: (D) Bread-making yeast is a fungus

Explanation: Saccharomyces yeast is a fungus used for fermentation. Nostoc and Anabaena are cyanobacteria, Paramecium is a protist, Penicillium a fungus, and lichens involve a fungus together with a photosynthetic partner.

50. Which organism lacks a nuclear membrane?

[AIPMT Prelims, 2012]

(A) Nostoc

(B) Penicillium

(C) Agaricus

(D) Volvox

Answer: (A) Nostoc

Explanation: Nostoc is a cyanobacterium with prokaryotic cellular architecture. Its DNA is not enclosed by a nuclear envelope. The two fungi and the green alga listed are eukaryotic and possess nuclei.

49. What is another traditional name for cyanobacteria?

[AIPMT Prelims, 2012]

(A) Blue-green algae

(B) Protists

(C) Golden algae

(D) Slime moulds

Answer: (A) Blue-green algae

Explanation: Cyanobacteria were historically called blue-green algae because many are photosynthetic and contain blue phycocyanin pigments. Unlike true eukaryotic algae, however, they are bacteria lacking a membrane-bound nucleus.

48. Who is credited with introducing binomial nomenclature?

[TNPSC Group I Preliminary Examination, 2011]

(A) Charles Darwin

(B) Gregor Mendel

(C) Ernst Mayr

(D) Carolus Linnaeus

Answer: (D) Carolus Linnaeus

Explanation: Carolus Linnaeus established a consistent system of naming species with a genus followed by a specific epithet. The practice improves communication across languages and remains foundational despite continuing taxonomic revisions.

47. Microsporum belongs to the same kingdom as which organism?

[AIPMT Mains, 2011]

(A) Rhizopus

(B) Ascaris

(C) Taenia

(D) Wuchereria

Answer: (A) Rhizopus

Explanation: Microsporum causes fungal ringworm infections, and Rhizopus is another member of kingdom Fungi. Ascaris and Wuchereria are nematodes, while Taenia is a flatworm, all belonging to Animalia.

46. Methanogenic microorganisms occur abundantly in which environment?

[AIPMT Prelims, 2011]

(A) Hot sulphur springs

(B) Dry sulphur rock

(C) Cattle yards

(D) Well-aerated freshwater

Answer: (C) Cattle yards

Explanation: The rumen of cattle and decomposing dung provide anaerobic conditions that support methanogens. These archaea release methane and are important in the production of biogas from livestock waste.

45. Which association is incorrectly matched?

[AIPMT Prelims, 2011]

(A) Cassia-imbricate aestivation

(B) Root pressure-guttation

(C) Puccinia-smut disease

(D) Root-exarch xylem

Answer: (C) Puccinia-smut disease

Explanation: Puccinia species cause rust diseases, particularly wheat stem rust. Smuts are caused by other fungi such as Ustilago. The remaining pairings describe recognised botanical structures and physiological phenomena.

44. Black stem rust in wheat is caused by which organism?

[AIPMT Mains, 2010]

(A) Alternaria solani

(B) Ustilago nuda

(C) Puccinia graminis

(D) Xanthomonas oryzae

Answer: (C) Puccinia graminis

Explanation: Puccinia graminis is a basidiomycete rust fungus infecting wheat stems and other plant parts. Ustilago nuda causes loose smut, Alternaria solani early potato blight, and Xanthomonas oryzae a bacterial rice disease.

43. Which combination of statements is correct:
(a) methanogens are archaea;
(b) Nostoc fixes nitrogen;
(c) chemosynthetic bacteria make cellulose from glucose as their defining process;
(d) mycoplasmas have no cell wall?

[AIPMT Mains, 2010]

(A) Only (b) and (c)

(B) Only (a), (b), (c)

(C) Only (b), (c), (d)

(D) Only (a), (b), (d)

Answer: (D) Only (a), (b), (d)

Explanation: Methanogens produce methane and belong to Archaea; many Nostoc strains fix nitrogen; and mycoplasmas lack cell walls. Chemosynthetic bacteria instead gain energy by oxidising inorganic substances, so statement (c) is incorrect.

42. Organisms surviving extremely high temperatures and very acidic conditions belong chiefly to which pair?

[AIPMT Prelims, 2010]

(A) Liverworts and yeasts

(B) Eubacteria and archaea

(C) Cyanobacteria and diatoms

(D) Protists and mosses

Answer: (B) Eubacteria and archaea

Explanation: Certain bacteria and archaea possess specialised proteins and membranes enabling survival in hot, acidic environments. Most eukaryotic organisms in the other choices cannot withstand such combined extremes.

41. Which infectious agents consist of abnormal proteins?

[AIPMT Prelims, 2010]

(A) Satellite viruses

(B) Gemini viruses

(C) Prions

(D) Viroids

Answer: (C) Prions

Explanation: Prions are misfolded infectious proteins associated with transmissible spongiform encephalopathies. They differ from viroids, which are naked RNA, and viruses, which contain nucleic acid protected by a protein coat.

40. In Whittaker’s system, most unicellular eukaryotes are included in:

[AIPMT Prelims, 2010]

(A) Monera

(B) Protista

(C) Fungi

(D) Archaea

Answer: (B) Protista

Explanation: The traditional kingdom Protista includes a great variety of mostly single-celled eukaryotes. Monera comprises prokaryotes, while Fungi is predominantly multicellular, except for species such as yeasts.

39. Which disease-causing organism pair is wrong?

[AIPMT Prelims, 2009]

(A) Black wheat rust-Puccinia graminis

(B) Loose wheat smut-Ustilago nuda

(C) Vegetable root knot-Meloidogyne

(D) Potato late blight-Alternaria solani

Answer: (D) Potato late blight-Alternaria solani

Explanation: Late blight of potato is caused by Phytophthora infestans, while Alternaria solani causes early blight. The other disease associations are correct. Properly identifying pathogens involves distinguishing fungal, fungus-like and nematode parasites.

38. T. O. Diener discovered which infectious entity?

[AIPMT Prelims, 2009]

(A) Naked infectious DNA

(B) An infectious protein

(C) A bacteriophage

(D) Naked infectious RNA

Answer: (D) Naked infectious RNA

Explanation: Diener identified viroids as remarkably small RNA pathogens that lack the protein coat of ordinary viruses. Potato spindle tuber disease is a well-known example of a viroid-induced plant disorder.

37. Which organism performs photosynthesis that liberates oxygen?

[AIPMT Prelims, 2009]

(A) Oscillatoria

(B) Rhodospirillum

(C) Chlorobium

(D) Chromatium

Answer: (A) Oscillatoria

Explanation: Oscillatoria is a cyanobacterium using oxygenic photosynthesis with water as an electron donor. The other listed photosynthetic bacteria are known for forms of anoxygenic photosynthesis that do not release oxygen.

36. Thermococcus, Methanococcus and Methanobacterium are examples of organisms with which characteristic?

[AIPMT Prelims, 2008]

(A) They are bacteria equipped with mitochondria

(B) They are archaea with histone-like proteins related to eukaryotic histones

(C) They have no histone-like proteins at all

(D) They are bacteria with typical eukaryotic cytoskeletons

Answer: (B) They are archaea with histone-like proteins related to eukaryotic histones

Explanation: These genera belong to Archaea, many of which possess DNA-binding histone proteins related to eukaryotic core histones. Their genetic machinery combines distinctive archaeal characteristics with certain molecular similarities to eukaryotes.

35. Which microorganism generally has cellulose-rich cell walls?

[AIPMT Prelims, 2008]

(A) Saccharomyces

(B) Pythium

(C) Xanthomonas

(D) Pseudomonas

Answer: (B) Pythium

Explanation: Pythium belongs to the oomycetes, fungus-like organisms with cellulose-rich walls. True fungi such as Saccharomyces have walls rich in glucans and chitin, while bacterial walls generally contain peptidoglycan.

34. Which statement about archaea in the three-domain classification is correct?

[AIPMT Prelims, 2008]

(A) They differ completely from all other prokaryotes

(B) They are identical to eukaryotes in every trait

(C) They possess some distinctive characteristics absent from bacteria and eukaryotes

(D) They share no features with either bacteria or eukaryotes

Answer: (C) They possess some distinctive characteristics absent from bacteria and eukaryotes

Explanation: Archaea are prokaryotes but have distinctive membranes and biochemical systems. Some information-processing mechanisms resemble those of eukaryotes, while their small cells resemble bacteria. Neither complete identity nor complete separation describes them accurately.

33. Which pair is entirely composed of basidiomycetes?

[AIPMT Prelims, 2007]

(A) Puffballs and Claviceps

(B) Peziza and stinkhorn fungi

(C) Morchella and Agaricus

(D) Bird’s-nest fungi and puffballs

Answer: (D) Bird’s-nest fungi and puffballs

Explanation: Both bird’s-nest fungi and puffballs form basidiospores and belong to Basidiomycetes. Claviceps, Peziza and Morchella are ascomycetes, so pairings containing those genera are taxonomically mixed.

32. Which fungus causes ergot of rye?

[AIPMT Prelims, 2007]

(A) Uncinula

(B) Ustilago

(C) Claviceps

(D) Phytophthora

Answer: (C) Claviceps

Explanation: Claviceps purpurea is an ascomycete causing ergot disease and producing dark sclerotia in infected rye. These structures contain ergot alkaloids. Ustilago causes smuts, whereas Phytophthora causes several blight diseases.

31. Which organism is a slime mould?

[AIPMT Prelims, 2007]

(A) Physarum

(B) Thiobacillus

(C) Anabaena

(D) Rhizopus

Answer: (A) Physarum

Explanation: Physarum forms a multinucleate plasmodium and belongs among slime mould protists. Thiobacillus is a bacterium, Anabaena a cyanobacterium and Rhizopus a true fungus, despite some superficial similarities in appearance or nutrition.

30. Which statement about mycoplasmas is false?

[AIPMT Prelims, 2007]

(A) Their shapes are variable

(B) They are generally sensitive to penicillin

(C) Some cause diseases of plants

(D) They have been called PPLO

Answer: (B) They are generally sensitive to penicillin

Explanation: Mycoplasmas lack cell walls, making antibiotics directed against peptidoglycan synthesis, such as penicillin, ineffective. Their flexible membranes permit unusual shapes. Some species are pathogenic in plants and animals.

29. The vegetative multinucleate body of a slime mould is known as:

[AIPMT Prelims, 2006]

(A) Protonema

(B) Plasmodium

(C) Basidiocarp

(D) Mycelium

Answer: (B) Plasmodium

Explanation: A plasmodium is an extensive multinucleate mass of cytoplasm characteristic of certain slime moulds. It differs from the hyphal mycelium of fungi and the filamentous protonema found in the moss life cycle.

28. What is common to Trypanosoma, Noctiluca, Monocystis and Giardia?

[AIPMT Prelims, 2006]

(A) All are unicellular protists

(B) All move exclusively using flagella

(C) All form reproductive spores

(D) All are obligate parasites

Answer: (A) All are unicellular protists

Explanation: These organisms are all single-celled eukaryotic protists. Noctiluca is generally marine and free-living, while Monocystis and Trypanosoma are parasitic. Their methods of movement and life histories therefore differ considerably.

27. Which conditions favour the growth of Mucor on bread:
A. 25°C,
B. 5°C,
C. 5% humidity,
D. 95% humidity,
E. shade,
F. bright illumination?

[AIPMT Prelims, 2006]

(A) A, C and E

(B) A, D and E

(C) B, D and E

(D) B, C and F

Answer: (B) A, D and E

Explanation: Warm temperatures, high atmospheric humidity and shade promote bread mould growth by providing moisture and suitable conditions for fungal metabolism and spore germination. Cold, dryness and intense light are less favourable.

26. Which agent causes bovine spongiform encephalopathy, or mad-cow disease?

[AIPMT Prelims, 2006]

(A) Bacterium

(B) Prion

(C) Parasitic worm

(D) Virus

Answer: (B) Prion

Explanation: Bovine spongiform encephalopathy results from abnormal infectious prion proteins that induce misfolding of normal proteins in nervous tissue. Prions do not possess the genomes characteristic of bacteria, worms or viruses.

25. In a lichen, what benefit does the fungal partner chiefly supply to its photosynthetic partner?

[AIPMT Prelims, 2005]

(A) Atmospheric nitrogen fixation in every case

(B) Protection, attachment and absorption of water and minerals

(C) All photosynthetic sugars

(D) Oxygen from respiration

Answer: (B) Protection, attachment and absorption of water and minerals

Explanation: The fungal component protects the symbiosis, anchors it and absorbs water and nutrients. The algal or cyanobacterial partner usually provides carbohydrates through photosynthesis. This nutritional cooperation defines the lichen association.

24. Where do barophilic prokaryotes chiefly thrive?

[AIPMT Prelims, 2005]

(A) In frozen alkaline mountain ponds

(B) Only in barium-rich water

(C) In deep marine sediments under great pressure

(D) In water containing soluble barium salts

Answer: (C) In deep marine sediments under great pressure

Explanation: Barophiles, also called piezophiles, have adapted to very high hydrostatic pressure, such as that found in deep-sea sediments. The name derives from pressure rather than from the chemical element barium.

23. Auxospores and hormocysts are produced respectively by which organisms?

[AIPMT Prelims, 2005]

(A) Many diatoms and a few cyanobacteria

(B) Cyanobacteria and diatoms in that order

(C) A few diatoms and numerous cyanobacteria

(D) Many cyanobacteria and diatoms

Answer: (A) Many diatoms and a few cyanobacteria

Explanation: Auxospores allow diatoms to restore their cell size after successive divisions. Hormocysts are thick-walled specialised filaments formed by certain cyanobacteria. These reproductive or resting structures occur in different groups.

22. Which unicellular organism contains a macronucleus for routine activity and micronuclei for reproduction?

[AIPMT Prelims, 2005]

(A) Euglena

(B) Amoeba

(C) Paramecium

(D) Trypanosoma

Answer: (C) Paramecium

Explanation: Paramecium shows nuclear dimorphism typical of ciliates. The macronucleus regulates cellular activity, whereas the micronucleus is important in sexual processes such as conjugation. This arrangement distinguishes ciliates from many other protists.

21. Which feature is especially characteristic of mammals?

[AIPMT, 2004]

(A) Muscular diaphragm

(B) Four-chambered heart

(C) Rib cage

(D) Warm-blooded nature

Answer: (A) Muscular diaphragm

Explanation: A muscular diaphragm separating chest and abdominal cavities is a distinctive mammalian adaptation assisting breathing. Birds also possess a four-chambered heart and endothermy, while rib cages occur in several other vertebrate groups.

20. In which arthropod class is the body normally divided into head, thorax and abdomen?

[AIPMT, 2004]

(A) Myriapoda

(B) Crustacea

(C) Arachnida and Crustacea

(D) Insecta

Answer: (D) Insecta

Explanation: Insects ordinarily have three clear tagmata: head, thorax and abdomen. Spiders commonly have a cephalothorax and abdomen, whereas other arthropods show different patterns of segment grouping.

19. Which matches of animals and respiratory organs are accurate:
A. silverfish-tracheae;
B. scorpion-book lungs;
C. sea squirt-pharyngeal gills;
D. dolphin-skin?

[AIPMT, 2003]

(A) A and D

(B) A, B and C

(C) B and D

(D) C and D

Answer: (B) A, B and C

Explanation: Silverfish breathe through tracheal tubes, scorpions through book lungs and sea squirts through pharyngeal gill slits. Dolphins are mammals that breathe air through lungs rather than through skin.

18. Which pairing correctly associates an animal with a phenomenon?

[AIPMT, 2003]

(A) Pheretima-sexual dimorphism

(B) Musca-complete metamorphosis

(C) Chameleon-mimicry

(D) Taenia-polymorphism

Answer: (B) Musca-complete metamorphosis

Explanation: Musca, the housefly, undergoes complete metamorphosis through egg, larva, pupa and adult. Earthworms are generally hermaphroditic, and the other pairings do not describe the standard textbook examples intended here.

17. Through which structures does Hydra eliminate undigested food and dissolved nitrogenous wastes respectively?

[AIPMT, 2001]

(A) Mouth and mouth

(B) Body wall and body wall

(C) Mouth and body wall

(D) Mouth and tentacles

Answer: (C) Mouth and body wall

Explanation: Hydra has one gastrovascular opening, its mouth, used for food intake and expulsion of undigested material. Dissolved metabolic wastes diffuse across its thin body wall because it lacks specialised excretory organs.

16. Which organism in the following list has a post-anal tail?

[AIPMT, 2001]

(A) Earthworm

(B) A lower non-chordate invertebrate

(C) Scorpion

(D) Snake

Answer: (D) Snake

Explanation: A post-anal tail is a defining chordate character, present at least during development. Snakes are vertebrate chordates, although their external anatomy is specialised. A scorpion’s posterior sting-bearing region is not a chordate post-anal tail.

15. Which statement about mammals is correct?

[AIPMT, 2000]

(A) Platypus lays eggs

(B) Bats possess feathers

(C) Elephants are ovoviviparous

(D) Mammals do not have diaphragms

Answer: (A) Platypus lays eggs

Explanation: The platypus is a monotreme, an egg-laying mammal. Bats have hair rather than feathers, elephants give birth to live young, and a muscular diaphragm is characteristic of mammals.

14. Which structure is NOT universally present in all chordates?

[AIPMT, 2000]

(A) Diaphragm

(B) Coelom

(C) Pharyngeal clefts during development

(D) Dorsal hollow nerve cord

Answer: (A) Diaphragm

Explanation: A muscular diaphragm is characteristic of mammals, not every chordate. The chordate body plan includes a dorsal hollow nerve cord, a notochord and pharyngeal slits at some developmental stage.

13. What feature is shared by Ascaris lumbricoides and Anopheles stephensi?

[AIPMT, 2000]

(A) Sexual dimorphism

(B) Metameric segmentation

(C) Obligate anaerobic respiration

(D) Endoparasitism

Answer: (A) Sexual dimorphism

Explanation: Male and female roundworms differ in size and tail structure, while male and female mosquitoes also differ in morphology. Ascaris is a nematode endoparasite, whereas Anopheles is an arthropod vector.

12. Which animal shows tissue-level organisation rather than cellular organisation?

[AIPMT, 2000]

(A) Sponge

(B) Hydra

(C) A liver fluke

(D) Ascaris

Answer: (B) Hydra

Explanation: Cnidarians such as Hydra exhibit tissue-level organisation, with specialised cell layers and a nerve net. Sponges show cellular-level organisation, while more complex flatworms and nematodes possess organs or organ systems.

11. Air-filled pneumatic bones occur prominently in which vertebrate class?

[AIPMT, 1998]

(A) Mammalia

(B) Reptilia

(C) Urodela

(D) Aves

Answer: (D) Aves

Explanation: Many birds possess hollow bones linked with air-sac systems, reducing skeletal mass while maintaining strength. This pneumatic skeleton is an important adaptation associated with avian flight and respiration.

10. Solenocytes are excretory cells found in which phylum?

[AIPMT, 1998]

(A) Platyhelminthes

(B) Arthropoda

(C) Annelida

(D) Aschelminthes

Answer: (A) Platyhelminthes

Explanation: Solenocytes are specialised terminal cells of protonephridial excretory systems described in certain flatworms. Their flagella or cilia drive filtrate through fine ducts. They are not the typical excretory organs of insects or annelids.

9. Which phenomenon is characteristic of the cnidarian Obelia?

[AIPMT, 1998]

(A) Metagenesis

(B) Morphogenesis

(C) Apolysis

(D) Paedogenesis

Answer: (A) Metagenesis

Explanation: Obelia exhibits alternation of polyp and medusa forms. Asexual budding in the polyp stage gives rise to reproductive medusae that produce gametes. This alternation is commonly termed metagenesis.

8. Which category accounts for the greatest number of described species among these groups?

[UPSC Civil Services Preliminary Examination, 1996]

(A) Fungi

(B) Flowering plants

(C) Insects

(D) Bacteria

Answer: (C) Insects

Explanation: Insects form the largest group of described animal species and substantially outnumber the listed alternatives. Their success is associated with small body size, flight, metamorphosis and adaptation to diverse terrestrial habitats.

7. What does the two-part scientific naming system introduced by Linnaeus signify?

[AIPMT, 1993]

(A) Two names assigned by different taxonomists

(B) One local and one Latin name

(C) A scientific and common name together

(D) A generic name followed by a specific epithet

Answer: (D) A generic name followed by a specific epithet

Explanation: Binomial nomenclature assigns a species a Latinised genus name and a specific epithet. The genus begins with a capital letter, whereas the epithet is lowercase; both are italicised when printed.

6. Which term refers to viruses infecting algae?

[AIPMT, 1993]

(A) Binal viruses

(B) Cyanophages

(C) Mycophages

(D) Phycophages

Answer: (D) Phycophages

Explanation: Phycophages are viruses whose hosts are algae. Cyanophages specifically infect cyanobacteria, while mycophages infect fungi. Such host-based terms classify viruses according to the organisms they parasitise.

5. All true fungi can be described as which type of organisms?

[AIPMT, 1993]

(A) Heterotrophs

(B) Autotrophs

(C) Only saprophytes

(D) Only parasites

Answer: (A) Heterotrophs

Explanation: All true fungi obtain organic food from other organisms or their remains. Some are saprotrophs, others parasites, and many form symbioses. They lack chlorophyll and therefore cannot be classified as photosynthetic autotrophs.

4. Which animal possesses nerve cells forming a net without distinct organised nerves?

[AIPMT, 1993]

(A) Hydra

(B) Tapeworm

(C) Earthworm

(D) Frog tadpole

Answer: (A) Hydra

Explanation: Hydra has a diffuse nerve net rather than a centralised brain or nerves. Cnidarians represent a relatively simple level of nervous organisation compared with the specialised neural structures of annelids and vertebrates.

3. Planaria, the liver fluke and Taenia solium all belong to which common group?

[AIPMT, 1993]

(A) Segmented annelids

(B) Intestinal nematodes

(C) Coelomate animals

(D) Flatworms

Answer: (D) Flatworms

Explanation: Planaria, Fasciola and Taenia are members of Platyhelminthes. Although their lifestyles differ substantially, all share a fundamentally flattened, triploblastic and acoelomate organisation that distinguishes them from roundworms.

2. Which sequence of taxonomic ranks is correctly arranged from higher to lower?

[AIPMT, 1992]

(A) Class, phylum, tribe, order, family, genus, species

(B) Division, class, family, tribe, order, genus, species

(C) Division, class, order, family, tribe, genus, species

(D) Phylum, order, class, tribe, family, genus, species

Answer: (C) Division, class, order, family, tribe, genus, species

Explanation: In descending hierarchy, division or phylum precedes class, followed by order, family, optionally tribe, genus and species. A tribe is an intermediate rank generally positioned between family and genus.

1. Who introduced the taxonomic term phylum?

[AIPMT, 1992]

(A) Georges Cuvier

(B) Ernst Haeckel

(C) Theophrastus

(D) Carolus Linnaeus

Answer: (B) Ernst Haeckel

Explanation: Ernst Haeckel introduced the term phylum in the nineteenth century for major organismal lineages. Cuvier had earlier described major structural divisions of animals without using this exact term.180 exam-attributed taxonomy PYQs | The number decreases by one for each question. Examination years are sorted newest to oldest. Last item: 1992.