Body fat levels of 6–10% for men and 12–19% for women are considered
a. high
b. just right
c. low
d. morbidly obese

The correct answer is : C. low
Average body fat for men lie between 18 - 24 % and average body fat for women lie between 25 - 31 %.  Men started to show some six packs at 10 % body fat.

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.