2021 · Q84
Which of the following statements about tropical rain forests are correct?
- 1The soils of tropical rain forests are quite infertile.
- 2The vegetation is evergreen, enabling photosynthesis to take place year around.
- 3They have been described as deserts covered by trees’.
- 4They are most productive land based ecosystem.
Select the correct answer using the code given below.
general-sciencebiotech-environment-science
- A2 and 4 only
- B1, 3 and 4 only
- C1, 2 and 3 only
- D1, 2, 3 and 4
Explanation
All four statements are correct. Tropical rainforest soils (oxisols and ultisols) are heavily leached by intense rainfall, leaving them nutrient-poor and quite infertile, since most nutrients are locked in the living biomass rather than the soil. The uniform warmth and moisture keep the vegetation evergreen, so photosynthesis continues year-round. Ecologists describe these forests as 'deserts covered by trees' precisely because of this paradox of lush growth on poor soil. With abundant heat, light and water, they record the highest net primary productivity of any terrestrial ecosystem.