The answer is because they have the 7 characteristics of life.
Only living things have all 7 of them, even if some inanimate objects have, they might only have a few.
These characteristics include movement, respiration, sensitivity, growth, reproduction, Excretion and nutrition.
Yes for example robots can move, or can respond to stimulus, but at the moment they can't reproduce or excrete. So they're not living things.
There are 6 genotypes possible I believe
You can tell a eukaryotic and prokaryotic cells apart by looking for the nucleus. Eukaryotic cells have a nucleus while prokaryotic does not.
Does this one work?