Question

Which of the following features do all gas exchanges have in common?
(A) They are enclosed within ribs.
(B) They are maintained at a constant temperature.
(C) The exchange surfaces are moist.
(D) They are exposed to air

Answer 1

There are many features which are common in all gas exchanges but the most important is related to the surface of that area where the gas exchange has to take place.

Complete solution:
The exchange of gases and respiration is essential if cells are to remain active, grow and divide. All the structures which were used as gas exchange have common as follows:
-They have an outsized area relative to the quantity of the organism.
-They are thin then have a brief diffusion pathway.
-They have a surface which is found to be moist where gases can dissolve first before they diffuse in or out.
-They are ready to maintain the diffusion gradient down which the gases can diffuse.
The transport of oxygen in the blood takes place through the Red blood cells (RBCs), during inhalation, oxygen is taken into the lungs and from the lungs, oxygen diffuses into the blood. As soon as it enters the blood, RBC is present where it binds to the haemoglobin. Out of 100, $3\%$ of oxygen is dissolved in the blood where $97\%$ of transported oxygen is bound to haemoglobin. This oxygen then diffuses in the tissues. The carbon dioxide is produced as a result of transpiration which takes place inside the body cells. From the cell the carbon dioxide has to diffuse into the blood where it is carried as:
-Carbaminohemoglobin, when it is bound to haemoglobin.
-Dissolved into the plasma.
-Bicarbonate ions.

So, the correct answer is ‘The exchange surfaces are moist.’

Note:
The lungs serve as the organ to exchange the two gases in the blood. The protein which is present inside the red blood cells that carry oxygen to the different cells of the body and also the carbon dioxide to the lungs is called haemoglobin.