Final answer:
The correct statement about BMI is that it cannot be used as an alternative for direct measures of body fat. BMI calculations are simple, cost-effective, but they have several limitations and do not measure body fat directly. The correct option is 3.
Step-by-step explanation:
Among the statements provided about Body Mass Index (BMI), the true statement is that BMI cannot be used as an alternative for direct measures of body fat. BMI is calculated using height and weight measurements, and it provides a generalized estimate of fatness.
It's a useful tool for population studies, but it has limitations. Specifically, BMI does not measure body fat directly nor does it account for muscle mass, bone density, overall body composition, and racial differences in body composition.
BMI is relatively inexpensive and easy to perform. It does not require costly equipment or extensive training, which makes it accessible for widespread use. However, it is important to consider that BMI can both underestimate the amount of body fat in people who are physically fit or muscular and overestimate it in individuals who have less muscle mass.
For children and teens, BMI is less reliable as an indicator of body fatness because of their ongoing growth and development. The traditional BMI formula has been modified for these age groups, but its use is still evolving.