In explaining buoyancy, which statement about body tissues is true?

• A. Fat is denser than muscle, decreasing buoyancy.
• B. Muscle is less dense than fat, increasing buoyancy.
• C. Fat tissue is less dense than muscle, increasing buoyancy.
• D. All tissues have the same density as water.

Answer: (C)

Buoyancy depends on how the overall density of the body compares to water. Fat tissue is less dense than muscle, so having more fat lowers the body's average density. For reference, fat is about 0.9 g/cm³, while muscle is about 1.06 g/cm³, and water is 1.0 g/cm³. Because fat is lighter than water and lighter than muscle, a body with more fat rises more easily in water. That’s why the statement that fat tissue is less dense than muscle, increasing buoyancy, is true. The other ideas aren’t accurate: fat isn’t denser than muscle, not all tissues share the same density as water, and muscle isn’t less dense than fat.