Which brief definitions correctly describe glycogen, ATP, free radicals, and hemoglobin in the context of exercise?

• A. Glycogen — dietary fat stored in adipose; ATP — a hormone regulating appetite; Free radicals — vitamins that prevent oxidation; Hemoglobin — carbohydrate transporter in blood.
• B. Glycogen — a fatty acid polymer used for long-term energy; ATP — a storage form of protein; Free radicals — inert molecules with no biological effect; Hemoglobin — an enzyme in mitochondria.
• C. Glycogen — stored carbohydrate in muscle/liver; ATP — immediate cellular energy currency; Free radicals — reactive molecules produced during metabolism that can damage cells; Hemoglobin — iron-containing protein in red blood cells that transports oxygen.
• D. Glycogen — the primary structural protein in muscle; ATP — a lipid that insulates nerves; Free radicals — a type of essential fatty acid that increases during exercise; Hemoglobin — a carbohydrate that fuels muscles.

Answer: (C)