Greetings! I have read/heard from various sources that none of the cells in my (or any other human's) body now are the same as they were seven (At least one source said nine years) years ago. I remember reading from one source that some cells don't "die" but all of the separate parts are replaced, so that the entire cell really is different, without having died. I remember being told that some memory cells are never replaced, and some brain cells are replaced after fifty years. Would they have changed all of their parts without dying, as mentioned above, in essence making them new cells? Am I a completely different person than I was less than a decade ago on the cellular scale? Thanks in advance.