12. Which is required for cells to pump ions against the concentration gradient?

A. ATP

B. Osmosis

C. Phospholipids

D. Water

The correct option is A) ATP

Explanation:

Some ions or molecules tend to move in the cell along a concentration gradient. Such types of movement is known as passive transport. In passive transport, molecules move from a higher concentration to a lower concentration. Such kind of movement doesn't require energy.

Other kinds of molecules or ions move against the concentration gradient i. e from a lower concentration to a higher concentration. Energy is required for these process to occur. The energy used is in the form of ATP.