Our lungs do not collapse whenwe expelled the air forcefully because our lungs do not ever full fill or empty of air completely.there will be a small amount of air that will be remaining in lungs there will be no matter how hard you expel air. so the lungs doesn't collapse after forceful expiration. if you like it mark as brainiest.

Our lungs are never completely empty.There is always some volume of air left in our lungs after we exhale the maximum we can.This left over volume of air or residual volume doesnot let the walls of our lungs to collapse while we exhale and more over it is only due to this residual volume that gaseous exchange continue to occur through our alveolis while we exhale.(when we exhale, most of the air is pumped out and during this moment the gaseous exchange would have stopped and we should have fallen short of oxygen but fortunately this doesnt occur...... Thanks to the residual volume. gaseous exchange continues for some time) normal residual volume around 1400 ml

Gaseous exchange refers to the process of oxygen entering the bloodstream and carbon dioxide being expelled from the body through the lungs. This exchange occurs in the alveoli, which are tiny air sacs present in the lungs.

After a forceful expiration, which is a strong and rapid exhalation, several changes occur in the respiratory system. Let's understand why option A, i.e., "gaseous exchange continues uninterrupted," is the correct answer.

Forceful Expiration and Gaseous Exchange:
During a forceful expiration, the diaphragm and intercostal muscles contract vigorously, causing the volume of the thoracic cavity to decrease. As a result, the pressure within the lungs increases, and air is expelled rapidly.

However, it is important to note that gaseous exchange occurs due to diffusion, which is the movement of gases from an area of higher concentration to an area of lower concentration. This process is not solely dependent on the movement of air in and out of the lungs, but also on the concentration gradients of oxygen and carbon dioxide.

Uninterrupted Gaseous Exchange:
Even after a forceful expiration, gaseous exchange continues uninterrupted due to the following reasons:

1. Oxygen Concentration Gradient: The alveoli are highly vascularized, meaning they have an extensive network of blood vessels. This allows for a constant supply of deoxygenated blood to come into contact with the alveolar walls. The concentration of oxygen in the alveoli is higher than in the deoxygenated blood, creating a concentration gradient. This gradient facilitates the diffusion of oxygen into the bloodstream, ensuring continuous gaseous exchange.

2. Carbon Dioxide Concentration Gradient: Simultaneously, the concentration of carbon dioxide in the deoxygenated blood is higher than in the alveoli. This concentration gradient allows for the diffusion of carbon dioxide from the bloodstream into the alveoli, enabling its removal from the body through expiration.

3. Passive Process: Gaseous exchange occurs passively, driven by the concentration gradients mentioned above. It does not depend on the active contraction of muscles or the movement of air. Therefore, even during a forceful expiration, the process of diffusion continues uninterrupted, ensuring a constant exchange of gases.

Conclusion:
In summary, gaseous exchange continues uninterrupted after a forceful expiration due to the concentration gradients of oxygen and carbon dioxide. The passive process of diffusion ensures that oxygen enters the bloodstream, and carbon dioxide is expelled from the body through the alveoli.