Florida Biology EOC Practice Test 2026 - Free Biology End-of-Course Practice Questions and Study Guide

Active transport is the process that uses energy to move substances against a concentration gradient. This means that the substance is being moved from an area of low concentration to an area of high concentration. This is the opposite direction of diffusion and facilitated diffusion, which both move substances from an area of high concentration to an area of low concentration. Osmosis also follows the movement of substances from an area of low concentration to an area of high concentration, but it does not require energy to do so. Instead, it is the movement of water through a selectively permeable membrane. Therefore, active transport is the only process listed that fits the description of moving substances against a concentration gradient.