Question

muscular floor of chest cavity..........
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Answer 1

Answer:

diaphragm'.

Explanation:

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Answer 2

Answer:

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Explanation:

The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.