When a cell uses ATP energy to transport a substance through a cell membrane from an area of lower concentration to an area of higher concentration, the cell is using

ACTIVE TRANSPORT

Explanation:

Generally, the transport of molecules across membranes can either be ACTIVE OR PASSIVE. Active transport are those transport that occurs against a concentration gradient i.e. from an area of low concentration of the substance to an area of high concentration, hence, will require energy input in form of ATP.

On the other hand, passive transport occurs down a concentration gradient and hence do not require energy to take place. Hence, based on the description above, when a cell uses ATP energy to transport a substance through a cell membrane from an area of lower concentration to an area of higher concentration, the cell is using ACTIVE TRANSPORT.

the correct answer is:

a population changes in response to a change in the environment.