Under which condition can actual humidity be high but evaporation still remain rapid?

Correct answer: When both temperature and wind speed are very high

Correct answer: D. Actual humidity refers to the amount of water vapour already present in the air, whereas evaporation depends on several conditions, especially temperature, wind movement, and the difference between the water surface and the surrounding air. High temperature gives water molecules more energy to escape from the liquid surface. Strong wind continually carries moist air away from that surface and replaces it with air that can accept more vapour. Thus evaporation can remain rapid even when the air already contains considerable moisture, provided the temperature and wind speed are both high. A is incorrect because calm air does not remove moist air efficiently. B is incorrect because low temperature reduces the energy available for evaporation. C is incorrect because saturated air has little or no capacity to accept additional vapour, so evaporation is greatly restricted. D is the best answer because it combines strong heating with effective removal of moist air. Do not confuse high actual humidity with zero evaporation; the rate also depends on atmospheric movement and temperature.