WHY do we get OLD?

 

The aging process is a real head-scratchier for scientists.

Healthy humans are capable of healing injuries,recovering from illnesses,and replicating their cells again and again.Why can't this process continue forever?old age and death are hardly helpful to our species'survival,after all.Scientists have studied nearly every type of animal-from short-lived fruit flies to age defying flatworms-to unravel this mystery.

According to one theory,our life span is programmed into our DNA,which jump-starts the aging process once we are beyond our reproductive years.Another theory holds that your cells have a sort of expiration date and can only reproduce so many times.