An extensive study was conducted on identical twins who were separated at birth. Among other things, the study showed that the individual from each pair who received better nutrition during childhood tended to be taller. This can best be described as an example of how:

a. mutation alters genotype.
b. mutation alters phenotype.
c. environment alters genotype.
d. environment alters phenotype.
e. multiple alleles having an effect on phenotype.

d. environment alters phenotype.

Explanation:

Phenotype refers to the physical characteristics of an organisms such as height, weight, color etc.

Genotype is the genetic composition of an organism.

The phenotype is usually as a result of the environment having an influence on the genotype.

In this case, the other twin is exposed to an environmental condition which is better nutrition. This better nutrition makes the twin taller. Tallness is a phenotypic trait.

This simply means environment altered the phenotype.

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