Where do the hyphens go in microorganism?

The correct placement of hyphens in "microorganism" typically does not require any hyphens, as it is a single, compound Word. However, if you're using it in a compound adjective form, such as "micro-organism-related studies," the hyphen would be used to clarify the relationship. In general usage, though, "microorganism" is written as one Word without hyphens.