Compare and contrast the role of environment and biology regarding individuals with phenylketonuria (PKU) and Down syndrome.

Every human trait is influenced by genes. Epigenetics refers to the series of complex exchanges between heredity and the environment. Researchers have discovered that human characteristics are epigenetic, meaning certain environmental influences can impact the way genes are expressed.
Tasks:
Create a 3- to 5-page Microsoft Word document responding to the following:
Compare and contrast the role of environment and biology regarding individuals with phenylketonuria (PKU) and Down syndrome.
Include a discussion on learning and personality development and cite evidence to support your analysis regarding these individuals.