Question

what is diaphragm option 1 the lining of lungs
option 2 sheets of muscles at the bottom of the rib cage
option 3 muscles which connects the ribs together​

Answer 1

Answer:

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.

Explanation: