In many of the studies we've seen researchers look at how much of human behavior is determined by genes and how much by the environment. this is known as the

 The answer is nature vs nurture debate. Our genes (nature) have a direct impact on our phenotype (physical appearance) and other biological traits including personalities. However, the environment (culture, childhood experiences, and etcetera) have an impact on our behaviors. This study of the nature's impact on our behavior is also a realm of epigenetics. This is the study in the changes of gene expression without any changes in the sequence of DNA (genetic material) of the organism. The environment, and age are significant in epigenetics.  Chemical modification of DNA nucleotides such as histone modification, methylation can be influenced by environmental factors.

the correct answer is 2 and 4