What is the science of classifying organisms into groups?

Taxonomy

Explanation:

Taxonomy is the science of naming, defining and classifying groups of biological organisms on the basis of shared characteristics.

The principal ranks in modern use are domain, kingdom, phylum, class, order, family, genus and specie

for the points

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.