Nitrifying bacteria obtain their chemical energy from: a. the reduction of no3- to nh4+. b. the formation of nh4+ from n2 gas. c. the oxidation of nh4+ to n2.

C. the oxidation of NH4+ to N2.

Explanation:

Nitrifying bacteria are specific types of bacteria that obtain their chemical energy by the oxidation of inorganic nitrogen compounds. The process of nitrification can be divided into two steps:

oxidation of ammonium to nitrite (performed by ammonia-oxidizing bacteria-AOB such as Nitrosomonas)oxidation of nitrite (NO2−) to nitrate (NO3−) performed by nitrite-oxidizing bacteria (NOB) such as Nitrobacter.

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.