Biology
Assertion (A): Diaphragm contracts and flattens downwards during inspiration.
Reason (R): Diaphragm relaxes and moves upwards to a dome shape during expiration.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Respiratory System
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Answer
Both A and R are True.
Reason — During inspiration, the diaphragm contracts and moves downward, becoming flat. This increases the volume of the thoracic cavity, allowing air to flow into the lungs. During expiration, the diaphragm relaxes and returns to its dome-shaped position. This reduces thoracic volume and pushes air out of the lungs.
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