Biology Questions. Having to DO with DNA And RNA.?

I can only answer the first one off the top of my head.... If DNA isn't replicated exactly, then you can have problems down the road. If the new DNA replicates, and there is another slight change in it, then eventually you could have completely new DNA. Since this doesn't happen, you usually die from some mutation or disease caused by having screwed up DNA. Even if you don't die, then you can get some pretty weird mutations.