Question 1:

Which of the following is the primary muscle involved in the process of inhalation?

Explanation: The primary muscle involved in the process of inhalation is the diaphragm. It contracts and moves downward, increasing the volume of the thoracic cavity and causing air to enter the lungs. Therefore, option A is correct.

Question 2:

Which structure is responsible for the exchange of oxygen and carbon dioxide in the lungs?

Explanation: The structure responsible for the exchange of oxygen and carbon dioxide in the lungs is the alveoli. These tiny air sacs have thin walls and a large surface area, allowing for efficient gas exchange between the air and the bloodstream. Therefore, option C is correct.

Question 3:

Which gas is primarily transported by red blood cells in the bloodstream?

Explanation: Oxygen is primarily transported by red blood cells in the bloodstream. It binds to hemoglobin, a protein found in red blood cells, and is carried to tissues throughout the body. Therefore, option A is correct.

Question 4:

What is the role of surfactant in the respiratory system?

Explanation: The role of surfactant in the respiratory system is to facilitate gas exchange. Surfactant is a substance produced by specialized cells in the lungs. It reduces the surface tension of the alveoli, preventing them from collapsing and allowing for efficient gas exchange. Therefore, option D is correct.

Question 5:

Which blood vessel carries oxygenated blood from the lungs to the heart?

Explanation: The pulmonary vein carries oxygenated blood from the lungs to the heart. It is the only vein in the body that carries oxygenated blood. Therefore, option B is correct.