Assessment of body is more revealing for determining potential health risks because it measures the proportion of lean muscle to body fat as compared to measuring a number on a scale

The answer would be composition

Body composition can be used to describe the amount of the lean muscle, bones, fat, water in the human body. The weight of a person doesn't always reflect their health status. There are a few factors that can make it different like the distribution of the fat and the ratio of the fat. people with higher height will have more muscle and bones, so their fat content would be less than a person with lower height but similar weight.

The answer is constant.