Question

active transport is defined by its ability to transport substances against their natural flow, requiring the usage of cellular energy. what direction do molecules move during active transport? high concentration to low concentration side to side low concentration to high concentration

Explanation:

Active transport is defined as the movement of substances against their concentration gradient, which means from an area of low concentration to an area of high concentration, requiring energy. The other options: "high to low" is passive transport (like diffusion), and "side to side" is not a standard description for active transport direction.

Answer:

low concentration to high concentration