Question

If you examined the human body on a chemical composition basis, which of the following combinations of elements would be most common?? (A) C, H, Ca, Cl (B) O, C, P, S (C) O, C, H, N (D) O, C, N, Na (E) C, N, Ca, S

Answer 1

Answer:

(C) O, C, H, N

Explanation:

Roughly 96% of mass of human body is made up of four elements which are oxygen, carbon, nitrogen and hydrogen.

Oxygen and hydrogen are predominantly found in the water, which makes up about 60% of body's weight. Carbon is synonymous with the life. The central role of carbon is due to fact that it has four bonding sites which allow for building of long and complex chains of the molecules. Moreover, these carbon bonds can be formed and also be broken with amount of energy which makes life alive. Nitrogen is found in organic molecules, including amino acids which make up the proteins, and nucleic acids which make up the DNA.