Answer the following question given this paragraph: 

The process in which a liquid changes to a solid is called freezing . The temperature at which a liquid changes to a solid is its freezing point. The freezing point of water is 0°C (32°F). Other types of matter may have higher or lower freezing points. For example, the freezing point of iron is 1535°C. The freezing point of oxygen is -219°C.


Q: What is the process by which a liquid changes to a solid?


A:
freezing