Zoology-Mechanism of Breathing

NEET Zoology Mechanism of Breathing MCQ Question

Type: MCQ-conceptual-Hard-Class 11

Which of the following statements correctly describe the mechanism of breathing?

A

Inspiration is caused by a decrease in thoracic volume, leading to lower intra-pulmonary pressure.

B

Expiration occurs when the diaphragm and inter-costal muscles relax, decreasing thoracic and pulmonary volume.

C

The conducting part of the respiratory system is primarily responsible for gas exchange.

D

During inspiration, atmospheric pressure is greater than intra-pulmonary pressure, causing air to flow into the lungs.

Correct Answer

Option B

Detailed Explanation

Statement B accurately describes the process of expiration as detailed in the NCERT context, where relaxation of muscles leads to decreased volume and increased pressure. Statement A is incorrect because inspiration is associated with an increase in thoracic volume, not a decrease. Statement C is also incorrect as the conducting part does not participate in gas exchange. Statement D correctly describes the pressure dynamics during inspiration, but does not fully capture the essence of breathing mechanics compared to statement B.

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