Enzymes function best at the normal pH level they were made to be in. Most work best at a neutral pH level (7), but some enzymes such as pepsin (located in the stomach) work best in very acidic pH levels. If the pH level becomes too acidic for the enzyme, it can lead to denaturing of the enzyme's active site.
Answer:
antibodies to a disease bacterium
Explanation:
B only in the nucleus and rough ER
The main function of the respiratory system is to allow the exchange of gases between the atmosphere and the lungs.
Hence,the only structure that carries out this function is the alveoli as other structures such as the nose,trachea and pharynx transport gases to the alveoli just so that it can can out its function.