Sometimes genes, for no known reason(s), change their form in a process called spontaneous

Sometimes genes change their form in a process without a reason and it's called spontaneous mutation. Spontaneous mutations occur with non-zero probability. And they occur even in an uncontaminated cell. They are characterized by the specific changes.

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.