Answer;
Single celled.
Microorganisms are typically single-celled and consist of bacteria, viruses, fungi, and protozoa.
Step-by-step explanation;
-Microorganisms or microbes is an organism that are microscopic and can not be seen with a naked eye. Microorganisms are usually single-celled, or unicellular organisms; however, some unicellular protists are visible to the naked eye, and some multicellular species are microscopic.
Microorganism mainly consist of bacteria, viruses, fungi and protozoa.