Which term refers to the loss of water in the form of water vapor from a plant?

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

Answer: (B)

Transpiration is the loss of water vapor from a plant, mainly through the stomata on the leaves. Water absorbed by roots travels up the xylem to the leaves, and when stomata open for gas exchange, water vapor exits while carbon dioxide enters for photosynthesis. This loss creates a pull that helps move water up the plant and also helps cool it. The rate depends on light, temperature, humidity, wind, and soil moisture. This process differs from evaporation (water loss from surfaces not specifically through plant tissues), condensation (water vapor turning into liquid), and osmosis (water movement across a semipermeable membrane).