How does the phenomena of survive of the fittest relates to peppered moth simulation?

Peppered moth stimulation is an experimental setup that show the behavior of moth in relation to their environment. The objective of the setup is to stimulate changes in moth population as a result of pollution and predation. 
Peppered moth stimulation relates to the survival of the fittest because the moth with the most adaptive ability will be able to survive despite the negative forces in the environment. The bright colored moth was able to survive the pollution in the environment and retains its colour while the black coloured moth change its colour to black due to the pollution int the environment.

Cotton was the very first

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.