Question

nerve cells need a special balance of sodium and potassium ions to send signals. to keep this balance, the cell membrane uses energy to pump sodium out and potassium in. this is an example of: active transport, because energy is used to move ions against their gradient passive transport, because the ions move naturally diffusion, because sodium and potassium spread out evenly osmosis, because water is moving with the ions

Explanation:

Active transport requires energy to move substances against their concentration gradient. Here, the cell membrane uses energy to pump sodium out and potassium in, which is characteristic of active transport. Passive transport doesn't require energy, diffusion is the passive spread of substances, and osmosis is the movement of water across a semi - permeable membrane, none of which match the described process.

Answer:

A. Active transport, because energy is used to move ions against their gradient