Understand that the incidence of mutations can be increased by exposure to ionizing radiation (for example gamma rays, X-rays and ultraviolet rays) and some chemical mutagens (for example chemicals in tobacco).
1. Mutation is the change in the base sequence of the gene. New alleles are produced
2. what causes mutation?
examples are: a) radiation: X-rays, UV-B rays (sunshine) can cause skin cancer
b) chemicals such as tar - they are called mutagenes and cause cancer - carcinogens