Question

The exhaled air mainly contains
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. None of the above

Answer 1

Hint: Exhalation is the process of movement of the air out of an organism. In animals, it is the movement of air from the lungs, to the external environment during breathing. It usually removes the waste products from the body.

Complete answer: Exhaled air mainly consists of more amount of carbon dioxide and less oxygen as carbon dioxide is considered as a waste product in the body and thus, the body eliminates it during the process of respiration. During the process of exhalation, the diaphragm and rib muscles relax which causes the lungs to decrease and expiration occurs. Breathing is the process of moving air into and out of the lungs which results in gaseous exchange with the internal environment of the organism, mostly by entering oxygen and removal of carbon dioxide. The main reason for exhalation is to get rid of carbon dioxide, which is the waste product of gas exchange in humans. The air gets into the body through inhalation. During this process, the air is taken in through the lungs. Diffusion in the alveoli allows for the exchange of oxygen into the pulmonary capillaries and the removal of carbon dioxide and other gases from the pulmonary capillaries to be exhaled. The diaphragm relaxes at the time when air is released, which pushes up on the lungs. The air flows through the trachea and into the larynx and pharynx and finally to the nasal cavity and oral cavity, where it is expelled out of the body.
Hence, the correct option is B.

Note: The gas is exchanged with the help of a connective tissue called the blood. Red blood cells contain haemoglobin that plays an important role in the gaseous exchange. It has a biconcave shaped structure that holds these gases efficiently.