Final answer:
The scale is not a method for determining a person's body composition, as it only measures total body weight, unlike specialized techniques such as underwater weighing, bioelectrical impedance, and dual-energy X-ray absorptiometry.
Step-by-step explanation:
The method that is NOT for determining a person's body composition among the given options is d. scale. A regular scale simply measures total body weight and does not provide detailed information about body composition such as the amount of fat, muscle, bone, and water.
Methods like underwater weighing, bioelectrical impedance (BIA), and dual-energy X-ray absorptiometry (DEXA) are specialized techniques that assess body composition by measuring the density of the body, the resistance to electrical currents, and the absorption of X-ray beams, respectively. Each of these methods provides more comprehensive information about the different components that make up a person's total body mass, which a scale alone cannot do. Underwater weighing involves submersion in water to measure body density, while BIA uses electrical signals, and DEXA applies low-dose X-rays to estimate various elements of body composition.
Air displacement, a method similar to underwater weighing, involves replacing water with air and measuring the volume of air displaced by a person's body to calculate body composition.