Which term describes the process by which water travels upward through a plant due to evaporation at the leaves?

• A. Adhesion
• B. Transpiration
• C. Umbra
• D. Doldrums

Answer: (B)

Transpiration is the process by which water evaporates from leaf surfaces, creating tension in the xylem that pulls a continuous column of water upward from the roots. This pull, often called the transpiration pull, is possible because water molecules stick together (cohesion) and also adhere to the walls of the xylem vessels (adhesion), helping the water column resist gravity as it moves toward the leaves to replace what was lost as vapor. The term specifically describes the overall upward movement driven by leaf evaporation, whereas adhesion is only one part of the mechanism, and the other terms refer to shade or wind conditions unrelated to how water travels up the plant.