Transpiration as Plant Water Loss

Steps:

• Define transpiration as the loss of water vapor from plant leaves to the atmosphere.
• Locate the process in leaf mesophyll cells where evaporation occurs.
• Trace the exit path through open stomata on the leaf surface.
• Compare options to select the one matching this evaporation and stomatal loss.

Why B is correct:

• Transpiration is defined in biology as the evaporation of water from mesophyll cell surfaces, followed by diffusion through stomata, which creates pull for xylem transport.

Why the others are wrong:

• A: Identical wording to B, serving as a distractor but not distinctly incorrect.
• C: Cuticle blocks water movement, preventing evaporation; transpiration occurs via stomata, not cuticle.
• D: Describes xylem transport (cohesion-tension mechanism) but not the evaporation loss itself.

Final answer: B