Answer:
The correct answer is - They have substances that counteract acids or bases to prevent the pH from changing
Step-by-step explanation:
All living organisms including humans are water-based systems, which implies that they rely intensely upon liquid equilibria, particularly acid-base equilibria. Hence, all the acid-base and pH ideas we have talked about so far are critical to the chemistry of organic or biological systems.
This is particularly significant for enzyme, which are proteins that go about as catalysts for all major biological reactions. Most enzymes just work inside a specific pH range. Because all natural cycles are subject to pH, cells and creatures must keep up a particular and consistent pH so as to keep their compounds in the ideal condition of protonation they have specific substances that counteract the acid and base to maintain pH.
for instance:
The pH of the Cytoplasm is maintained by the phosphate ion
The pH of the blood is regulated by the bicarbonate ion