2 The study of biometrics is not as simple as other fields of study about the body. Why is it more difficult to understand the role of energy in the body than other elements, like hormones? OA. Most basic principles of energy do not apply to the body. B. The body uses energy when in motion but not while at rest. OC. Some systems in the body require energy while other do not. OD. The body is very complex, so energy moves many different ways. Reset Next​