Water Evaporation Site in Transpiration

Steps:

• Transpiration is the loss of water vapor from plant leaves, driven by evaporation.
• Water travels from roots via xylem to mesophyll cells in leaves.
• It diffuses to moist cell walls, where evaporation into air occurs.
• Vapor then moves through intercellular spaces and exits via stomata.

Why C is correct:

• Evaporation happens directly from the wet surfaces of mesophyll cell walls, as defined in plant physiology where water vaporizes into the leaf's internal air spaces.

Why the others are wrong:

• A: Intercellular spaces contain humid air but are not the evaporation site; vapor forms there after wall evaporation.
• B: Leaf surface (cuticle) is waxy and minimizes evaporation; main loss is internal.
• D: Stomatal pores are exit points for vapor diffusion, not the evaporation location.

Final answer: C