2 results found for physical

In his lecture Professor Christian Rene de DuvŽ gives a rough overview on the history of life starting about 3.5 billion years ago with the first cells up to the appearance of the first primates 70 million years ago, and he states that all organisms....

During the past century a number of chemical and physical risk factors for human cancers have been identified. Only relatively recently, mainly during the past 30 years, infectious agents have been identified as important human carcinogens. Besides....