Answer to Question 1
c
Answer to Question 2
Gene expression is regulated in many ways, including DNA methylation; histone methylation, acetylation, or phosphorylation; and transcription factors. More recently, non-coding RNAs, such as the miRNAs, have been identified as playing a regulatory role as well. All of these regulatory mechanisms can be influenced by early programming in response to nutrition and other environmental factors in fetal life or infancy, as well as throughout the lifespan.