Height and weight are used to assess what measurement?

Height and weight are fundamental measurements used to calculate Body Mass Index (BMI), which is a widely utilized tool to assess an individual's body composition. BMI is derived by taking a person's weight in kilograms and dividing it by the square of their height in meters. This calculation provides a numerical value that helps categorize individuals into various weight classifications, such as underweight, healthy weight, overweight, and obese.

The importance of BMI lies in its ability to provide a general indication of whether a person has a healthy body weight in relation to their height, which is particularly useful in large population studies and for basic health screening. While BMI does not directly measure body fat percentage or muscle mass, it serves as a quick indicator to identify potential health risks associated with weight. In this context, height and weight together are essential for determining BMI, making this the correct answer.

Other options like body fat percentage and muscle mass index require more specific measurements or tools beyond just height and weight, and hydration levels are not assessed directly through these metrics.