Question

what is microorganism?

Answer 1

I guess it's one that's too small to be seen with the naked eye. So that includes bacteria, fungi, algae,protozoa and viruses (if you think they are alive).

Answer 2

virus ARE NOT ALIVE ... a microorganism is a living thing which is too small to small to seen without any aid, that is ... it is too small to be seen with the naked eye.

Answer 3

virus ARE NOT ALIVE ... a microorganism is a living thing which is too small to small to seen without any aid, that is ... it is too small to be seen with the naked eye.

Answer 4

virus ARE NOT ALIVE ... a microorganism is a living thing which is too small to small to seen without any aid, that is ... it is too small to be seen with the naked eye.

Answer 5

Micro = small, so... as others have said, very small organisms, specifically those in the microscopic dimensions.

I'd just like to add that microorganisms are not all single-celled: rotifers, for example, are smaller than many protists (single-celled eukaryotes), but they're actually multicellular organisms.