Answer:
Option (4).
Step-by-step explanation:
Respiratory system may be defined as the system involves in the exchange of gases between the tissue, lungs and the outside environment. The respiratory system involves nose, mouth, larynx, trachea, lungs, brochi, alevoli and alveolar ducts.
The oxygen is inhaled in the body and carbon dioxide is exhaled out from the body. The oxygen is transferred into the blood stream by binding of oxygen with hemoglobin. The oxygen is diffused in to body due to the partial pressure difference of oxygen and carbon dioxide.
Thus, the correct answer is option (4).