Class 11 NEET Biology Biomolecules Questions

(c) : Carbon, hydrogen, oxygen and nitrogen are called four big elements of living body they make up about 99% of the mass of most cells. As C,H,O and N are lightest elements so the bonds they form are the strongest covalent bonds. So that the compounds formed are stable, varied in size and shapes. Carbon constitutes more than 50% of the dry matter. It has been observed that human body contains 0.5% hydrogen, 18.5% carbon, 65% oxygen and 3.3% nitrogen. Other elements are present in very lesser amount.