Answer:
d. 60
Step-by-step explanation:
Both the American College of Sports Medicine and the U.S. Department of Health and Human Services recommend at least 60 minutes of exercise daily for youth under the age of 18. This has been determined to be a good daily dose of exercise in order to allow healthy growth and development of youth below the age of 18th. Which is also why Physical Education classes in the United States are mandatory and last 60 minutes.