The part of Earth that is liquid water is called the

Hydrosphere

Explanation:

The wording is quite confusing but if you are talking about the 'spheres' of earth's bio-systems, then the answer should be: The part of Earth that is liquid water is called the Hydrosphere

A nucleus is the cell's control centre but the cell membrane is what controls what comes in and out depending whether it is selectively permeable or semi permeable; therefore, the answer would be C because it take control and manages everything in the cell