Question

Assertion (A) : The rate of breathing in aquatic organisms is much faster than in terrestrial organisms. Reason (R) : The amount of oxygen dissolved in water is very high as compared to the amount of oxygen in air.

Give reasons for the following : (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory pigment in the blood takes up oxygen and not carbon dioxide. (iii) During anaerobic respiration, a 3-carbon molecule is formed as an end product instead of CO₂ in human beings.