Question

Assertion: Larger organisms have specialised respiratory pigments for delivery of oxygen to the different parts of the body.
Reason: Diffusion is faster than direct transportation.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not a correct explanation of A.
• C. A is true but R is false.
• D. A and R are false.

Answer 1

The correct option is C A is true but R is false.

Oxygen is required by most organisms for obtaining energy from the food they eat via the process of respiration. In simple organisms oxygen is directly absorbed from the atmosphere and transported across the body via diffusion. In larger organisms, however, diffusion is not enough to transport oxygen throughout the body due to the complex body structure and the consequent high energy demand to sustain the bodily functions. Thus such organisms depend on a much bulkier mode of transportation of oxygen. The oxygen is absorbed with the help of a respiratory pigment (ex- haemoglobin in humans) and transported to the various body parts via the circulatory system.