A) The process which led to drooping of leaves is transpiration.

Here are the answers to question 3.

a) The process which led to drooping of leaves is transpiration.

b) The leaves drooped in the hot afternoon because the rate of transpiration (water loss from leaves) was higher than the rate of water absorption by the roots. High temperatures in the afternoon increase the rate of evaporation, leading to excessive water loss and a reduction in turgor pressure within the plant cells, causing the leaves to become flaccid and droop. In the morning, temperatures are lower, and water loss is less, allowing the plant to maintain turgor.

c) The importance of transpiration includes:

• Creating a transpiration pull that draws water and dissolved mineral salts from the roots up to the leaves.
• Providing a cooling effect for the plant as water evaporates from the leaf surface.
• Facilitating the uptake of carbon dioxide for photosynthesis by keeping the stomata open.