What facts would you select to show the major significance of the element carbon in the human body?

Explanation:

Carbon (C) is one of the most important elements that comes into greater proportion in the basic constitution of our organism. This chemical element, together with hydrogen, oxygen and nitrogen are the quadripods (CHON), essential and primordial in protein synthesis and so many other organic compounds.

Carbon, one of the most versatile elements ever found, is responsible for most existing compounds and is present in the major biological cycles of living things.

About carbon we can say that:

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds