Final answer:
Socioeconomic status is a key determinant of physical activity in adults, affecting access to both safe environments and healthy food choices, which in turn influences overall physical activity levels.
Step-by-step explanation:
Among the determinants of physical activity in adults, socioeconomic status stands out as one of the most influential. Access to a safe environment for physical activities like walking or biking to work or markets can be limited by high crime rates or the lack of food options in a neighborhood. Affordable healthy food options are not always available, especially in urban areas or poorer neighborhoods, which may lead one to rely on high-calorie fast food as their primary source of nutrition. This ties directly to the level of physical activity an individual can maintain. Factors such as genetics, access to sports facilities, and climate do play roles, but socioeconomic status has a pronounced impact because it affects both the built environment people live in and the lifestyle choices they can make.