7 years. By the time you are 7 yrs old, there's not a single
   cell in your body that is the same as it was when you were born.
   14 21 #science
   [vine id = "M57jQ1EUJgd"]
   7 years. By the time you are 7 yrs old, there's not a single
   cell in your body that is the same as it was when you were born.
   14 21 #science