Only about 3 percent of the worlds water is fresh, and even less than that is usable, because most of it is locked up in glaciers or in permanent snow fields.
The correct answer is D.
Answer:
The cell membrane (also called the phospholipid bilayer or the plasma membrane) is one of the most important structures a cell has. If you think of the cell as a really popular nightclub, the membrane is the bouncer. It decides what enters and exits the cell.