The original post: /r/askscience by /u/Playful_Economics713 on 2024-11-10 03:38:46.

I feel like this is a dumb question, but I genuinely want to know. How do scientists find out how many organisms or just tiny things in large quantities in general are there? If you look up “how many organisms are in the human body?” It’ll say 39 trillion. If you look up “why do cats have a good sense of smell?” It’ll tell you they have 200 million olfactory receptors.

How did they count that? How did they round it to that? I’ve asked google this questions in multiple different ways but I don’t get the exact answer. I’m sorry if this seems like a dumb question ! I hope it doesn’t.