International Sports Sciences Association (ISSA) Trainer Practice Exam 2026 - Free Trainer Practice Questions and Study Guide

The human body is primarily composed of Lean Body Mass and Body Fat, making this answer the most accurate. Lean Body Mass includes all the tissues in the body that are not fat, such as muscles, organs, bones, and water. This component is crucial for overall health, as it plays a vital role in metabolism, strength, and mobility.

Body Fat, on the other hand, serves important functions, including energy storage, insulation, and protection of vital organs. Understanding the balance and significance of these two components is essential for evaluating one's health, body composition, and fitness levels.

While options such as muscle and bone are indeed important components of Lean Body Mass, they do not encompass the entirety of it. Additionally, water and electrolytes are critical for various physiological functions, yet they represent specific aspects of bodily needs rather than the overarching structural composition. Blood and plasma pertain to the circulatory system and do not define the primary physical structure of the body itself in the broader context.