Coal is best used as a
Fuel
Paint
Fertilizer
Conductor

A. Fuel.

Explanation:

Coal is extensively used as a fuel in many countries for the production of electricity. When coal is heated, the heat energy is used to convert the liquid water into steam which is used to move turbines in the electric power plant. When these turbines moves, the electricity is produced. This fossil fuel is also used for warming of rooms and cooking delicious foods.

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.