Which factor is more helpful for evaporation?

Correct answer: High temperature

Direct answer: B, high temperature. Evaporation is the change of liquid water into water vapour from the surface of a liquid. Heating gives water molecules more energy, so more molecules can escape from the surface and evaporation becomes faster. Follow the steps: water is present as a liquid; heat increases molecular movement; energetic molecules leave the surface; therefore a higher temperature generally increases evaporation. A is wrong because low temperature usually reduces molecular energy and slows evaporation. C is wrong because darkness itself is not the controlling factor; evaporation can occur in darkness if suitable conditions exist. D is wrong because stagnant or already moist air does not provide a helpful condition; moving, relatively dry air generally supports faster evaporation. The wording asks for the most helpful factor among the choices, so B is the best answer, even though wind, exposed surface area and dry air can also affect the rate. Memory cue: more heat, faster evaporation; cooling promotes condensation.