The correct match for microorganisms and their sizes is:
bacteria--2 micrometers
For clarification:
- Viruses typically range in size from about 20 to 300 nanometers, so both "viruses--1 centimeter" and "viruses--10 micrometers" are incorrect.
- The size of bacteria generally ranges from about 0.5 to 5 micrometers, so "bacteria--10 nanometers" is incorrect.