Final answer:
The specific grade for the U.S. on its 2015 "Report Card" for Physical Activity is not provided, but evidence suggests a likely unfavorable assessment as 8 out of 10 Americans fail to comply with recommended activity levels. These recommended levels include 150 to 300 minutes of moderate-intensity exercise or 75 to 150 minutes of vigorous-intensity exercise per week, plus muscle-strengthening activities.
Step-by-step explanation:
The grade for the U.S. on its "Report Card" for Physical Activity in 2015 is not directly stated in the information provided. However, we can infer that the U.S. might not have received a favorable grade considering the 2018 report from the American Heart Association, which estimates that 8 out of 10 Americans do not meet the physical activity guidelines set by the Department of Health and Human Services. These guidelines suggest that adults should engage in at least 150 to 300 minutes per week of moderate-intensity aerobic activity, or 75 to 150 minutes per week of vigorous-intensity aerobic activity, and include muscle-strengthening activities on 2 or more days per week.
The data indicates that a significant portion of the population is not achieving the recommended levels of physical activity, which could lead to a poor national grade for physical activity levels. It is crucial for public health to encourage and facilitate regular exercise as it brings myriad benefits, including disease prevention and enhanced quality of life.