Active transport requires energy because it usually involves the movement of
A. substances in the gas phase, such as oxygen and carbon dioxide.
OB. substances from an area of high concentration to an area of low concentration
OC. substances that can easily pass through the cell membrane, such as water.
D. substances from an area of law concentration to an area of high concentration.

D

Explanation:

When a substance moves from low to high concentration it is moving against its concentration gradient, which requires more energy.

A. It depends on where it is moving, not the substance

OB. This is describing diffusion

OC. Does not require energy, it is passive transport through a semi-permeable membrane

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.