Which of the following is an example of a physical change related to aging?

The choice indicating reduced healing capacity is the correct answer because it directly relates to a physical change that occurs as individuals age. With advancing age, the body's ability to repair itself diminishes due to a variety of factors, including decreased cellular regeneration and the overall slowing of metabolic processes. This reduced capacity can impact how individuals recover from injuries, surgeries, and illnesses, making it a significant aspect of the aging process.

In contrast, increased metabolism is generally not associated with aging; rather, metabolism often slows down with age. Enhanced flexibility is typically not a physical change seen in older adults, as flexibility tends to decrease due to muscle stiffness and joint changes. Improved lung function is also misleading because while there can be variation in lung function among older adults, overall lung capacity and function often decline with age due to factors like reduced elasticity of lung tissue. Therefore, reduced healing capacity stands out as a definitive physical change related to aging.