Cancers are more prevalent in the elderly because the mechanism of cell division becomes faultier with age.

Cancer develops in older people because of their prolonged exposure to carcinogens such as sunlight, radiation, environmental chemicals, and substances in the food we eat. Mutations also occurs as a result of random errors when cell's DNA is copied therefore it divides. As a result human cells accumulate more mutations the longer we live. Moreover, changes in tissues and organs with advancing age renders cells' micro environment more favorable to the development of cancer. Other factors related to age that may play a role in cancer prevalence in older people include, term effects of chronic inflammation, cancer promoting DNA changes caused by oxygen free radicals, less effective DNA damage repair mechanisms, and weakening of the immune system.

To kill bacteria from our body especially from stomach

They are k strategist i think