If all human cells replace themselves every 7 years, why can scars remain on you body your entire life?

Question

If all human cells replace themselves every 7 years, why can scars remain on you body your entire life?

In: Biology

Answer 1

You could ask why you still have arms or a head, too. Or why you can’t regrow a lost arm. It’s because your body doesn’t just create a whole new body, it maintains and replaces the structures that are already there with new cells that are the same type as the old cells were.