ENVIRONMENT FOR UPSC PRELIMS 2020 , SOLUTION OF TEST-29

1 . Solution (d)

2 . Solution (c)

3 . Solution (a)
Equatorial rain forests have thick canopy cover which does not allow the sunlight to reach the floor. There is stiff competition to between the trees to catch the maximum sunlight. Due to this there is very little undergrowth.

4 . Solution (a)
The plants prepare their own food by the process of photosynthesis. The process has two phases, the light reaction and the dark reaction. The light reaction takes place in the presence of sunlight, while the dark reaction does not require light and continues both during day and night. The byproduct of photosynthesis is Oxygen gas.
The plants burn their food to produce energy for their survival. This process is respiration. The plants take in O2 and release CO2. Since light reaction does not take place during night, the respiration dominates. That’s why it is not wise to sleep under a tree at night as it releases a lot of Carbon dioxide.

5 . Solution (b)

6 . Solution (a)
Apart from stomata plants and trees also breathe through lenticles, which are small pores present on their stem.
Many desert plants have their stomata in deep pits to minimize water loss by transpiration and not evaporation.

7 . Solution (d)

8 . Solution (c)
Detritivores (e.g., earthworm) break down detritus into smaller particles. This process is called fragmentation. By the process of leaching, watersoluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts. Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This process is called as catabolism.

9 . Solution (d)

10 .  Solution (c)