I would asy thd answer would be d if its not my bad .
Answer:
An allele is a viable DNA (deoxyribonucleic acid) coding that occupies a given locus on a chromosome. Usually alleles are sequences that code for a gene, but sometimes the term is used to refer to a non-gene sequence. An individual's genotype for that gene is the set of alleles it happens to possess.
C) Natural selection
When something happens in nature and something changes all of a sudden, the animals tend to adapt to what gives them more chances of survival. As a result, a large amount of the population would attempt to adapt in a way that helps them survive.
Carolus Linnaeus recognized the vital role of the internal environment and suggested that objective of mechanisms within the body is to preserve the constant conditions of the internal environment.
He was later known as the creator of current modern system of naming animals called binomial nomenclature
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