Final answer:
Physical activity is any movement that requires energy expenditure, while exercise is a planned and structured type of physical activity. The talk test is used to determine the intensity of physical activity.
Step-by-step explanation:
Physical activity is any bodily movement produced by skeletal muscles that requires energy expenditure. It includes activities such as walking, gardening, and household chores. On the other hand, exercise is a type of physical activity that is planned, structured, and repetitive, to improve or maintain physical fitness and health.
The talk test is a useful tool to determine the intensity of physical activity. During moderate-intensity aerobic activity, a person should be able to talk but not sing. During vigorous-intensity activity, a person should not be able to say more than a few words without pausing for a breath.