Question

Why do lungs cannot expand or contract on their own? ​

Answer 1

Answer:

The lungs do not contain muscles and are unable to expand and contract on their own. ... When you inhale, the diaphragm contracts and drops down. This lowers the air pressure in the chest cavity which causes air to enter the lungs, causing them to expand.

hope this helps you

Answer 2

• Lungs cannot expand or contract on their own because, in order for expansion and contraction to take place in any body part, there is a need for flexible tissue.
• Lungs do not contain muscle and hence they cannot expand or contract on their own.
• The diaphragm is a muscle that is located below the lungs and is responsible for the contraction and expansion of the lungs.
• When we  breathe in, the diaphragm flattens and contracts, moving away from the lungs creating a void(vacuum) inside our chest which allows air to gush in and fill into our lungs .
• When the diaphragm relaxes it de-flattens and the space inside the chest reduces which forces the air to rush out of the lungs and so we breathe out.