Question

Which of the following process occurs in respiration?

• A. Osmosis
• B. Diffusion
• C. Pressure gradient
• D. Both B and C

Answer 1

The correct option is D Both B and C

Breathing is a process that involves the exchange of gases in the lungs. This exchange of gases occurs in the alveoli by a the process of Diffusion. During the inhalation process, the volume of lungs increases due to contraction of diaphragm. This leads to decrease in the pressure of thoracic cavity which is also relatively less than the atmospheric pressure. Thus due to pressure gradient between atmosphere and thoracic cavity, the air from outside rushes into the lungs. Therefore the correct answer is option D