How does regular exercise maintain a healthy respiratory system?

a) it cilia in the lungs eliminate mucus.

b) it lungs from becoming too large.

c) it lungs exchange gases at a slower rate.

d) it lungs become more efficient at gas exchange.

Option D

Explanation:

It helps lungs to become more efficient by improving the gas exchange in the lungs. Regular exercises improves the cardio-respiratory fitness making it easier for the heart to be supplied with oxygen.

Staying fit and active is important for the people who are suffering from cardio respiratory disorders must exercise regularly  in order to keep their heart fit.

The people suffering from respiratory disorders such as blockage should walk and exercise regularly.

a lot ig i am not sure