Plant: Economic Importance

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Q40. Which fibre is obtained commercially from the husk of coconuts?

[RPSC — Practice]

1. Coir
2. Jute
3. Flax
4. Silk

Answer: (A) Coir

Explanation: Coir is extracted from the fibrous mesocarp or husk of coconut fruits. It is used in ropes, mats, mattresses and horticultural growing media. Unlike cotton seed hairs or jute stem bast, coir is a fruit-husk fibre.

Q39. Crotalaria juncea is grown commercially mainly for which purpose?

[UPSC CDS — Practice]

1. Sunn hemp fibre and green manure
2. Coffee beans
3. Quinine-rich bark
4. Edible potato tubers

Answer: (A) Sunn hemp fibre and green manure

Explanation: Crotalaria juncea, known as sunn hemp, provides useful stem fibre for ropes and other products. It is also cultivated as green manure and a cover crop because it grows quickly and contributes biomass and soil-management benefits.

Q38. Which plant is widely cultivated as a source of teak timber?

[RRB Group D — Practice]

1. Tectona grandis
2. Coffea arabica
3. Glycine max
4. Cicer arietinum

Answer: (A) Tectona grandis

Explanation: Tectona grandis supplies teak, a durable hardwood widely used for furniture, doors and construction. Its timber is valued for workability and natural durability. Unlike annual food crops, timber trees require longer growth cycles and careful forest or plantation management.

Q37. Shisham timber is obtained from which tree?

[MPPSC — Practice]

1. Dalbergia sissoo
2. Cedrus deodara
3. Carica papaya
4. Zea mays

Answer: (A) Dalbergia sissoo

Explanation: Dalbergia sissoo, commonly called shisham or Indian rosewood, provides hardwood used in furniture and carpentry. It is especially associated with riverine and subtropical landscapes in the Indian subcontinent. Cedrus deodara supplies deodar timber instead.

Q36. The desert tree khejri has which botanical name?

[RAS — Practice]

1. Prosopis cineraria
2. Shorea robusta
3. Tectona grandis
4. Corchorus capsularis

Answer: (A) Prosopis cineraria

Explanation: Prosopis cineraria, or khejri, is economically and ecologically important in the Thar Desert. It provides fodder, fuelwood and edible pods called sangri. Its suitability for arid landscapes makes it significant to traditional agroforestry systems in Rajasthan.

Q35. Which botanical name denotes sal, an important timber tree?

[WBCS — Practice]

1. Shorea robusta
2. Dalbergia sissoo
3. Cocos nucifera
4. Coffea arabica

Answer: (A) Shorea robusta

Explanation: Shorea robusta is sal, a major forest tree yielding strong timber used in construction and other products. Sal-dominated forests also support ecosystem services and livelihoods. Scientific identification helps distinguish sal from teak and shisham in forestry questions.

Q34. Which resin-producing medicinal plant is known as guggul?

[SSC CGL — Practice]

1. Commiphora wightii
2. Papaver somniferum
3. Pisum sativum
4. Daucus carota

Answer: (A) Commiphora wightii

Explanation: Commiphora wightii is the guggul plant, valued for a fragrant gum-resin traditionally used in medicinal formulations. It grows in arid regions, and unsustainable resin extraction can threaten natural populations. Commercial demand therefore makes cultivation and conservation particularly important.

Q33. Which statement about natural rubber is correct?

[UPSC CSE — Practice]

1. It is extracted mainly from mineral ores
2. It is largely polyisoprene obtained from latex
3. It is the same as jute bast fibre
4. It is extracted from wheat grains

Answer: (B) It is largely polyisoprene obtained from latex

Explanation: Natural rubber is composed mainly of cis-1,4-polyisoprene and is harvested as latex, especially from Hevea brasiliensis. The latex is processed into useful elastic material. Rubber differs chemically and structurally from cellulose-based plant fibres such as cotton and jute.

Q32. Which state accounts for about three-fourths of India’s jute production?

[RRB NTPC UG CBT-I — 2026]

1. West Bengal
2. Bihar
3. Assam
4. Odisha

Answer: (A) West Bengal

Explanation: West Bengal dominates Indian jute cultivation because of fertile alluvial soils, a warm and humid climate and ready access to river water. The Hooghly belt also developed processing mills and transport links, creating a historically important jute economy.

Q31. Which industry uses cotton as a principal raw material?

[RRB NTPC UG CBT-I — 2026]

1. Textile industry
2. Iron and steel industry
3. Cement industry
4. Mining industry

Answer: (A) Textile industry

Explanation: Cotton supplies natural cellulose fibre to textile manufacturing. Ginning separates fibre from seeds, spinning produces yarn and weaving or knitting creates fabric. Cotton cultivation and processing link agriculture with large-scale industrial employment and consumer clothing production.