which fossil fuel must migrate into pockets in order for humans to extract it? petroleum uranium

Brief Explanations:

First, we need to recall what fossil fuels are. Fossil fuels are formed from the remains of ancient organisms and include coal, petroleum, and natural gas. Uranium is not a fossil fuel; it's a radioactive element used in nuclear energy. Petroleum (oil) is a fossil fuel that, during its formation and geological processes, migrates into porous rock formations (pockets) like reservoirs, which allows humans to extract it through methods like drilling.

Answer:

A. Petroleum