Biology
During inspiration in humans the diaphragm and external intercostal muscles:
- Both contract
- Contract and relax respectively
- Both relax
- Relax and contract respectively
Respiratory System
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Answer
Both contract
Reason — During inspiration the diaphragm contracts and moves downward, increasing the vertical space in the thoracic cavity. The external intercostal muscles also contract, pulling the ribs upward and outward, increasing the volume of the chest cavity. This increases the thoracic volume and reduces pressure, allowing air to flow into the lungs.
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