Answer:
The correct answer would be the C) lungs.
Lungs are the pair of air-filled spongy organs.
They are mainly associated with the exchange of gases (carbon dioxide and oxygen) in the body.
The alveoli are the group of tiny air-sacs present in the lungs which form the site of gas exchange.
The oxygen from the alveolar site diffuses into the blood and carbon dioxide from the blood diffuses into the alveolar site.
The oxygen is then transported to all cells of the body with the help of circulatory system whereas carbon dioxide is removed out of the body as a part of exhaled air.
