What is the effect of exhaling and filling lungs on buoyancy?

• A. No effect
• B. Increases drag
• C. Increases buoyancy
• D. Decreases buoyancy

Answer: (C)

Buoyancy depends on how much air you have in your lungs. Filling the lungs with air increases the body's overall volume without adding much weight, so it displaces more water. More displacement means a greater buoyant (upward) force, making you float more easily. In short, inhaling to fill the lungs increases buoyancy, while exhaling reduces it.