The study of changes in phenotype that are not related to changes in the DNA and that may result from the interaction between the genotype and the environmentA. pleiogenetics

B. adaptation

C. epigenetics

D. menarche

E. homeoplasty

The correct answer is C. epigenetics

Explanation:

Epigenetics is the study of change in the phenotype that occurs not due to change in the DNA sequence but because of gene expression modification. So here we study the changes that occurred in phenotype, not in genotype.

DNA methylation, histone modification, etc can be responsible for the epigenetic changes in an organism. In DNA methylation, a methyl group or methyl cap is added to the DNA segment which prevents the expression of some genes.

The skin cell, brain cell, and muscle cells have the same DNA but due to epigenetic change (change in expression), they look different. So the correct answer is C. epigenetics.