The answer for your question is Monitor
Some examples are alcohol fermentation, lactic acid fermentation and in decomposition of organic matter.
I'm not entirely sure on this one... But I think it's 1. cell division helps animals repair old cells..
like please
They can enter your blood stream (via breathing/ingesting) and once in your bloodstream they can enter cells and mutate your dna, which can cause cancer/birth defects/ reproductive harm