group b. is called the control group. it is important to compare the 2 groups for any similarities. this determines if the medications in group a are working like intended. to keep track of side effects w/group a..
Answer: These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if an error is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed to the next generation.
Common examples of physical contaminants include hair, bandages, fingernails, jewelry, broken glass, metal, paint flakes, bone, the body parts of pests, or pest droppings.