What factors affect a swimmer's buoyancy?

Buoyancy is the ability of a swimmer to float in water, and it is affected by multiple factors, which is why the selected answer provides a comprehensive understanding. Body composition plays a crucial role, as a person's proportion of fat versus muscle can influence their overall density; fat is less dense than water and aids in buoyancy, while muscle is denser and can hinder it.

Water salinity also significantly affects buoyancy. In saltwater, where salinity is higher, swimmers tend to float more easily compared to fresh water because the increased density of the water helps support the swimmer's body. The technique used by a swimmer can enhance or reduce buoyancy as well; effective breathing techniques allow for proper air storage in the lungs, which helps maintain buoyancy.

Considering these three factors together provides a complete picture of what influences a swimmer's buoyancy, making this answer the most accurate choice. The other options fail to consider the full range of influences, simplifying the complexity of buoyancy in swimming.