UPSC Prelims 2021 · GS Paper I
Question 60: Environment and Ecology
“Leaf litter decomposes faster than in any other biome and as a result the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees.” This is the most likely description of
AnswerUPSC’s answer is (d).
The passage describes the tropical rain forest. Warm, humid conditions all year make leaf litter decompose faster than in any other biome, so little humus builds up and the soil surface is often bare. Competition for light drives vegetation upwards, so apart from the trees, most plants are climbers (lianas) or epiphytes living on tree branches. Coniferous, dry deciduous and mangrove forests do not combine these features.
Why each option is right or wrong
- (a) Wrong: coniferous forest litter decays slowly in cold conditions.
- (b) Wrong: dry deciduous forests have a dry season that slows decomposition and have fewer epiphytes and climbers.
- (c) Wrong: mangroves are tidal forests with stilt and breathing roots, not epiphyte-rich with bare ground.
- (d) Right: rapid decomposition, bare soil, climbers and epiphytes mark the tropical rain forest.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper I, Series A. The paper on upsc.gov.in.