Here's why:

* Boiling is a process where water changes from a liquid to a gas (steam) due to heat. This is a form of evaporation.

* The other options don't fit:

* STEAM is the gaseous form of water, not the process itself.

* HEAT is the energy needed for evaporation but not the process itself.

* DRIP refers to liquid falling in drops, not turning into gas.

* DAMP refers to moisture, not the process of evaporation.