Kills many disease-causing bacteria that may have been ingested.
a. pepsin
b. bile
c. gastrin
d. hydrochloric acid

D. Hydrochloric acid

Explanation:

The hydrochloric acid is produced by the cells present on the lining of the stomach walls. The function of the hydrochloric acid in the stomach is to provide an acidic environment for the digestion of food. The acidity in the stomach is responsible for the activation of the enzymes which supports the digestion of proteins present in the food stuff. Also the acidic environment facilitates the death of the disease causing pathogens like bacteria. This way the hydrochloric acid plays role in providing the internal immunity to the body.

image result for describe the various types of gene mutationsghr.nlm.nih.gov

the types of mutations include: missense mutation: this type of mutation is a change in one dna base pair that results in the substitution of one amino acid for another in the protein made by a gene. nonsense mutation: a nonsense mutation is also a change in one dna base pair.

explanation:

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a