Question

when you exercise, your muscle cells make extra carbon dioxide as waste. because there is more carbon dioxide inside the cells than in the blood, it naturally moves out of the cells across the membrane without any energy being used. this movement is an example of: active transport, because the cell spends energy to move carbon dioxide exocytosis, because the cell packages and pushes out the carbon dioxide passive transport, because carbon dioxide spreads out on its own from high to low concentration osmosis, because carbon dioxide is carried out by water

Explanation:

Passive transport moves substances from high - to low - concentration without energy. Here, CO₂ moves from cells (high concentration) to blood (low concentration) without energy use. Active transport requires energy. Exocytosis involves packaging of materials. Osmosis is for water movement, not CO₂ in this context.

Answer:

C. Passive transport, because carbon dioxide spreads out on its own from high to low concentration