During which phase change is heat energy absorbed by a substance?

evaporation

Explanation:

The process of converting a liquid to a gas is called evaporation. 600 cal is needed to convert 1g of water to water vapor at 0 °C or 540 cal at 100 °C.

The thermal energy absorbed by the molecules of a liquid during evaporation is used only to give them the movement needed to escape from the liquid's surface and become a gas. This energy, which is later released as heat when the vapor is liquid again, is called latent heat of vaporization.

the correct answer is:

a population changes in response to a change in the environment.