The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the industrial revolution. In the mid-nineteenth century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. By about 1900, approximately 90% of the moths around industrial areas were dark colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and therefore were eating more light moths. Recently, use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species?

a. Yes, because natural selection has affected the frequency of the two different forms.
b. Yes, because they have completely different coloration.
c. No
d. Yes, because they are reproductively isolated based on habitat

The answer is C - No

Explanation:

The two forms of moths cannot be considered as separate species because the different colors possessed by the moths was an example of "survival of the fittest". The white colored body of the white moth was beneficial in clean environment while the dark colored body of the dark moth was beneficial in polluted environment like Birmingham as this also acted as a form of effective camouflage against birds. This was effective camouflage because dark moths on clean trees and white moths on trees with darkened soot were easily caught by birds.

The two species are therefore not different species but are only trying to survive and escape the birds by using camouflage and making their colors the same with their environment to blend.

No. Generally a change in environmental factor can only affect the chances that a particular allele will appear in a population or not, It can never account   for the chances of  emergence  of the new species by mutation ,and therefore  variation can not take place and  new species  can not emerge, The answer is NO

Explanation:

Speciation(Allopatric Speciation) the  formation of new species can  only  arise  when population of species of organisms are separated by Geographical  isolation through physical barriers, storms, island

or  

When  extra chromosomes occur in  cells (polyploidy) that is Sympatric Speciation . Now,since the two species are  not Geographically isolated ot posesses polyploidy, but just difference in allele frequency by   effects of environmental  factors(selective pressure)  on expression of the allele for wing color a new species can not be formed.

Generally a change in environmental factor can only affect the chances that a particular allele will appear in a population or not, It can never account   for the chances of  emergence  of the new species by mutation ,and therefore  variation can not take place and  new species  can not emerge, The answer is NO