Classify each method or description of membrane transport as either passive or active by dragging the label to the correct box.

When substances move across the plasma membrane of a cell, they do so while either going down the concentration, which means from higher concentration to lower concentration, or against the concentration gradient, which means from lower concentration to higher concentration.

Passive transport occurs when movement is down the concentration gradient; whereas, active transport, which involves the use of energy, occurs against the concentration gradient.