Why do skeletal muscle cells typically contain more mitochondria than skin cells?

• A. Muscle cells have more mitochondria primarily to increase their capacity for protein synthesis on ribosomes.
• B. Skin cells have more mitochondria than muscle cells because they need to produce digestive enzymes for the body.
• C. Muscle cells require more mitochondria because they perform most of the body's detoxification reactions.
• D. Muscle cells have higher ATP demands for contraction, so they contain more mitochondria to support aerobic respiration.

Answer: (D)