This is the process of matter changing from the liquid to the solid state?

The process is called freezing.

Explanation:

The process in which matter changing from the liquid to the solid state is called Freezing. Generally the freezing point of liquid like  water is 32°F or 0°C. Freezing is just the opposite of melting in which a solid melted to liquid. different liquid has different freezing point. the freezing point of liquid nitrogen at a pressure of one atmosphere is -345.8°F.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

c is the correct answer hope this !