Question

b. Upward and downward movement of
diaphragm occurs consecutively.
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Answer 1

Explanation:

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Pas 100700

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Answer 2

Answer:

Diaphragm is a partition comprising muscles that is present between the thoracic cavity and abdominal cavity. When a person breathes, there is upward and downward movement of diaphragm that occurs simultaneously. When we inhale, the ribs rise up while the diaphragm lowers down at the same time causing a pressure decrease on lungs. This promotes free movement of air into lungs through the nostrils. Likewise when the ribs return to their normal position, the diaphragm rises up leading to an increase in pressure inside the lungs. This helps in movement of the air outside the nostrils.