Environmental science is an interdisciplinary that integrates biology, physics and geography (including zoology, chemistry, plant science,oceanology, geology, ecology, mineralogy, even atmospheric science to the study of the environment, and the solution of environmental problems. Environmental science emerged from the fields of natural history and medicine including forensics. Currently, it provides an integrated, quantitative, and interdisciplinary approach to the investigation of environmental systems. It is now known that in the field of medicine most environmental events can be impacted by epigenetics. In biology , epigenetics is the study of stable changes in cell function (known as marks) that do not involve alterations in theDNA sequence. The Greek prefix epi- (ἐπι- "over, outside of, around") in epigenetics implies features that are "on top of" or "in addition to" the traditional genetic basis for inheritance. Epigenetics most often involves changes that affect the regulation of gene expression, and that persist through cellular division up to at least two generations. Such effects on cellular and phenotypic traits may result from external or environmental factors, or be part of normal development. It can also lead to diseases such as cancer, psychosis, and even reward deficiency or addiction liability.