Which of the following indicates a decrease in physiological function due to aging?

The indication of a decrease in physiological function due to aging is represented by a decrease in flexibility. As individuals age, various physiological changes occur in the body, leading to reduced elasticity of muscles, tendons, and other connective tissues. This often results in a diminished range of motion and an overall decrease in flexibility.

Flexibility is crucial for maintaining mobility, posture, and balance, and its decline can increase the risk of injuries and affect overall physical performance. Factors contributing to this decrease include changes in collagen, alterations in muscle composition, and a generally more sedentary lifestyle that can accompany aging.

In contrast, the other options indicate either stability or improvement in physiological functions. For example, an increase in muscle strength and overall endurance may occur as a result of exercise and physical activity, countering some effects of aging, while no change in metabolism suggests that metabolic functions remain stable, which is not necessarily a sign of decline.