Answer
Free radicals come from ionizing radiation which is emitted from radioisotopes. They are also produced as a result of metabolic reactions and sometimes by white bloods when they kill off bacteria. They also come from preservatives in food. Free radicals are harmful because they destroy molecules and are thus carcinogenic(causing some cancers ) and damage heart tissue. The body is protected from free radicals by the production of antioxidants.
Work Step by Step
Pg. 46 and Pg.44 The section on Ionizing Radiation
