Not to be the "actually"🤓 guy, buuuuut:

> I think a more appropriate word for "a lot" is "often".

I'd say "a lot" is more appropriate, as "often" seems to kind of imply that it's the same change all over your body.

> Any time a mutation occurs, it alters what was already there, it doesn' create something new.

Well.... technically it can ||a mutation like e.g. duplication can happen, where that gene can then mutate and start doing wonky stuff||

> Between extreme causes of mutation you can find autoimmune diseases and cancer

Very true, those are then the examples that are bad for the whole organism. As you already said most mutations don't really do much, and if they do usually PCD sets in or the cell simply won't function and die off that way.