Which plant process involves the loss of water vapor from the leaves?

• A. Evaporation
• B. Condensation
• C. Transpiration
• D. Sublimation

Answer: (C)

Transpiration is the plant process in which water is lost as vapor from the leaf surface, primarily through openings called stomata. Water travels from the roots through the xylem to the leaves, and some of it evaporates from the internal leaf tissues and exits to the air. This loss helps pull water up the plant, supports nutrient transport, and helps cool the leaf. Stomata open to let in carbon dioxide for photosynthesis, so water vapor exits alongside gas exchange. The rate of transpiration rises with higher temperature, lower humidity, more air movement, and drier soil, and drops when humidity is high or soil moisture is limited. Evaporation is the general loss of water from any surface, condensation is vapor turning into liquid, and sublimation is solid turning directly into vapor.