What is transpiration?

• A. The loss of water vapour from plant leaves.
• B. The process of photosynthesis.
• C. The uptake of minerals from the soil.
• D. The release of carbon dioxide from leaves.

Answer: (A)

Transpiration is the loss of water vapour from plant leaves, mainly through openings called stomata. When stomata are open to allow carbon dioxide to enter for photosynthesis, water vapour can also escape from the leaf surfaces. This evaporation and diffusion of water move water up from the roots through the xylem, creating a transpiration stream that helps transport minerals and maintain cell turgor. It’s not photosynthesis, not mineral uptake, and not the release of carbon dioxide—those describe other processes.