The motor point is usually located at the center of the muscle mass where the motor nerve enters the muscle.
Definition A carcinogen is defined as something that can directly cause cancer. This can be a chemical substance, a virus, or even the medications and radiation we use to treat cancer. While many cancers are caused by a carcinogen or combination of carcinogens, the tendency to develop cancer may also be inherited as part of our genome.
Chemical Carcinogens. Chemical carcinogens can be classified into one of four groups according to their chemical nature: organic carcinogens, inorganic carcinogens, fibers, and hormones.