What is the process by which water vapor is released from plants into the atmosphere?

• A. Evaporation
• B. Infiltration
• C. Transpiration
• D. Runoff

Answer: (C)

Transpiration is the correct answer because it specifically refers to the process by which water vapor is emitted from plant leaves into the atmosphere. This process occurs when plants absorb water from the soil through their roots, and then, through tiny openings called stomata on their leaves, release moisture into the air. Transpiration plays a crucial role in the water cycle and helps regulate plant temperature, contributes to nutrient uptake, and maintains the overall moisture balance in the ecosystem.

In contrast, evaporation refers to the process of water turning from liquid to vapor, typically from surfaces like soil or water bodies, rather than directly from plants. Infiltration is the process by which water enters the soil from the surface, allowing it to recharge groundwater supplies, and runoff is the water flow that occurs when excess rain or melting snow flows over the ground rather than being absorbed. Each of these processes plays a distinct role in the hydrological cycle, but only transpiration specifically describes the water vapor release from plants.