Free radicals are a kind of sometimes harmful free molecules produced by the human body when consuming oxygen. Many people believe that free radicals are the culprit behind the aging of the body. Because some researchers have found that the amount of free radicals in the human aging process is constant increase. Any of the following can weaken the above conclusions:. ['There are still many disputes about the specific process of human aging.', 'Free radicals will rise in the process of combating aging.', 'Prolong the life of the body by artificially increasing the number of free radicals.', 'Instability of chromosomal structure is the cause of human aging.']