When Researchers Followed a Large, Representative Sample of U

When researchers followed a large, representative sample of U.S. youths from ages 9 to 17, they found that __________.

A) two-thirds of all students received physical education in high school
B) daily free-time physical activity declined with age, more so for girls than boys
C) a majority of participants engaged in regular exercise outside of school hours
D) half of all students experienced a daily physical education class in high school