Energy is added to change the conversion of solid ice to liquid and then to gaseous steam.
EXPLANATION:
Solid, liquid and gas are the three states of matter. Here one state is converted to another state due to a change in energy resources in the system. Solid ice melts to a liquid state as the temperature increases. The ice particles move faster resulting in the conversion of solid ice to water.
This liquid has more energy than solid ice.And this liquid on further heating results in the rise of temperature and water moves up as steam, such that it becomes gas. Extra energy is added when the water reaches the boiling point and is changed to a gaseous state. Thus the energy transfer is concluded in the above process.