The answer is; catalyst
These proteins are called enzymes. They work by lowering the activation energy of reactants and hence speed up the biochemical reaction. They are not affected in the process hence one enzyme molecule can catalyze many reactions. An example of such an enzyme is carbonic anhydrase that enables carbon dioxide to dissolve in blood plasma as carbonic acid.
The answer is; medulla oblongata and pons.
In this region of the brain, there are chemoreceptors that can detect changes in the pH of the blood. These are called central chemoreceptor. There are also chemoreceptors in the arteries called peripheral chemoreceptors. When these chemoreceptors detect a drop in the blood PH (due to increased dissolved carbon dioxide in the blood), the depth and rate of breathing is increased in the lungs.
Convergent evolution according to my records
The answer for this question is the second one so b or 2