Final answer:
Answer C) 'Less stress', is not a social benefit but a mental health benefit of physical activity. Social benefits typically involve interactions and contributions to a community, whereas stress reduction primarily affects individual mental health.
Step-by-step explanation:
The question which asks for identifying the physical activity benefit that is not a social benefit can be addressed by examining the benefits listed. While new friends, widened social networks, and contribute to society are directly related to social benefits, less stress is a mental health benefit associated with physical activity. Therefore, the correct answer to this question is C. Less stress.
Physical activity is known to reduce disease risk and improve overall health, including cardiovascular and muscular fitness, bone density, and cognitive function. Social benefits of physical activity include establishing new friendships and contributing to community and societal welfare.
Although social support plays a significant role in improving health outcomes and can influence health behaviors, the reduction of stress is an effect that occurs within the individual and is not considered a social benefit. This reduction of stress enhances the individual's mental health through improved body image, self-esteem, and protection against stress-related health issues.