Which one of the following statements regarding the benefits of physical activity is most accurate? a. the health benefits of physical fitness are generally dependent upon body weight. b. older adults gain the least benefit of all age groups for being habitually physically active. c. the risks of injury and sudden heart attack during physical activity outweigh the benefits of being active for older adults. d. health benefits of physical activity can be found in children and adolescents, young and middle-aged adults, and older adults.