Answer:
The correct answer is a) all of these
Step-by-step explanation:
Human body developed many mechanisms to regulate the pH of the body fluid. Carbon dioxide in the blood forms carbonic acid which neutralize the extra base and decrease the pH of blood.
Bicarbonate ions in the blood helps in neutralizing the extra acid in the blood and is reabsorbed by kidneys. Excretion of excess H⁺ ions from kidney also helps in regulating the pH of body fluid.
Almost all the proteins acts as buffer because they have charged regions which can bind to H⁺ or OH⁻ ions thus provide buffering capacity to the blood.
Thus, the correct answer is a all of these.