UPSC Prelims 2021 Question:

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

Explanation: 

• Tropical rainforests are found closer to the equator where it is warm. It is a hot, moist biome where it rains all year long. It is known for its dense canopies of vegetation that form three different layers.
  
  
• The top layer or canopy contains giant trees that grow to heights of 75 m or more. This layer of vegetation prevents much of the sunlight from reaching the ground. Thick, woody vines are also found in the canopy. They climb trees in the canopy to reach for sunlight. For this purpose, evolution of growth forms such as lianas, epiphytes, climbers and stranglers is a characteristic unique to rainforests.
  
  
• The middle layer, or understory, is made up of vines, smaller trees, ferns, and palms. The bottom layer or floor of the rainforest is covered with wet leaves and leaf litter. This material decomposes rapidly in the wet, warm conditions sending nutrients back into the soil.
  
  

Therefore, option (4) is the correct answer.

Subject: Geography | Natural Vegetation & Wildlife