Final answer:
The optimal body fat percentage for males aged 17-20 is 12-20%, and for females of the same age group, it's 20-30%. These percentages cater to differences in sex, such as hormonal and reproductive requirements, and physical activity levels.
Step-by-step explanation:
The allowable body fat percentage for males and females in the 17-20 age group is as follows: for males, it is between 12% and 20%, and for females, it is between 20% and 30%. These ranges indicate the optimal fat content for health and functionality, taking into account factors such as sex, age, and physical activity level. The percentage varies because females generally require more fat mass for reproduction and hormonal differences. In measuring body fat percentage, methods like the skin-fold test can be used, which is noninvasive and fairly accurate.