Question

The four elements making $99$% of living system are

• A. $CHOS$
• B. $CHOP$
• C. $CHON$
• D. $CNOP$

Answer 1

Answer: (C)

$CHON$

Oxygen is the most abundant element for the living organism. It is used for respiration. The oxygen inhaled supports the oxidation of food and releases energy. It plays an important role in the oxidative phosphorylation occurring in the mitochondria. The process produces energy in form of ATP.

Nitrogen is an important component of the amino acids which is a monomer of protein.

Carbon and hydrogen is an important constituent of carbohydrates which is an instant source of energy.

So, the correct answer is option C.