AP BIOLOGY

Detailed explanation-1: -Because identical twins develop from a single fertilized egg, they have the same genome. So any differences between twins are due to their environments, not genetics. Recent studies have shown that many environmentally induced differences are reflected in the epigenome.

Detailed explanation-2: -Positive experiences, such as exposure to rich learning opportunities, and negative influences, such as malnutrition or environmental toxins, can change the chemistry that encodes genes in brain cells-a change that can be temporary or permanent.

Detailed explanation-3: -Environmental factors such as food, drugs, or exposure to toxins can cause epigenetic changes by altering the way molecules bind to DNA or changing the structure of proteins that DNA wraps around.

Detailed explanation-4: -Mutations can occur during DNA replication? if errors are made and not corrected in time. Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation.