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.