In a multicellular organism, which type of cell would be expected to contain the greatest number of mitochondria per cell, and why?

• A. Cardiac muscle cells, because they require large amounts of ATP for continuous contraction
• B. Mature skeletal keratinocytes in the outer epidermis, because they have high rates of oxidative metabolism
• C. Red blood cells, because they generate ATP primarily through oxidative phosphorylation
• D. Adipocytes, because their primary role is rapid ATP production to support constant contractile activity

Answer: (A)