Question

During inhalation, diaphragm and rib muscles
(a) relaxes and contract respectively
(b) both rela
(c) contracts and relax respectively
(d) both contract.​

Answer 1

Answer:

When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

Hope it helps uh

Answer 2

Answer:

When the internal intercostal muscles contract and diaphragm relax, the ribs move .downward and inward and the diaphragm becomes convex {dome shaped), 

thus decreasing the volume of the thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration).