5) Internal signals affect gene expression by using signal transduction pathways. Regulatory genes encode a protein, which needs gene expression. Regulatory elements are non-coding regions of DNA that regulate the transcription of close genes. Transcription factors are normally proteins that bind with specific sequences of DNA to regulate gene expression and the transcription rate. These non-environmental factors affect gene expression and gene regulation by turning genes off or on.

6) There are multiple environmental factors that relate to identical twins. Environmental factors have an effect on variations between two identical twins. For example, diet is a specific factor that can change a twin’s phenotype from the other. When in the womb, one twin might receive more nutrients than the other. This can result in variations in weight and metabolism among the twins. After birth, there are other environmental factors that can cause variation like personal exercise or other life decisions that may affect the twin’s phenotypes differently. Non-environmental factors that happen inside the womb may be one twin obtaining a genetic condition while the other one does not. This is extremely rare, but it does cause phenotype variation between the twins.

7) The genetic variability of two cousins whose parents are both identical twins would be the cousins would be genetic siblings. In other words, the cousins will have the same genetic variability as two siblings. Due to the