The Clydesdale is a draft horse breed from Lanarkshire, Scotland, and its name was inspired by the River Clyde. The Clydesdaleâs history goes back to the mid-1700s, when native stocks were mated with larger Flemish horses and then selected for use in agriculture and for all types of heavy hauling, including transport through the streets of Glasgow.
Definition. 1  A carcinogen is a substance that causes cancer (or is believed to cause cancer). 2  A carcinogenic material is one that is known to cause cancer. 3  The process of forming cancer cells from normal cells or carcinomas is called carcinogenesis. A carcinogenic material is one that is known to cause cancer. 2  The process of forming cancer cells from normal cells or carcinomas is called carcinogenesis.
Written By: Carcinogen, any of a number of agents that can cause cancer in humans. They can be divided into three major categories: chemical carcinogens (including those from biological sources), physical carcinogens, and oncogenic (cancer-causing) viruses. 1  Most carcinogens, singly or in combination, produce cancer by interacting with DNA in cells and thereby interfering with normal cellular function.