The mass that includes muscles, vital tissues, organs, and bone is called lean body mass (LBM).

Here's a breakdown:

* Muscles: The largest component of LBM, responsible for movement and metabolic processes.

* Vital Tissues: Includes organs like the heart, lungs, liver, kidneys, and brain. These are essential for survival.

* Organs: A broader term than vital tissues, encompassing all the functional units of the body.

* Bone: Provides structure, support, and protection for the body.

LBM is distinct from body fat. It is often considered a better indicator of overall health and fitness than body weight alone, as it reflects the amount of metabolically active tissue in the body.