Here's why:

* Eukaryotic cells have a nucleus and other membrane-bound organelles, which are structures that perform specific functions within the cell. They are complex and are found in animals, plants, fungi, and protists.

* Prokaryotic cells are simpler and lack a nucleus and other membrane-bound organelles. They are found in bacteria and archaea.

While there are a few types of prokaryotic cells in the human body (mainly bacteria in our gut microbiome), the vast majority of our cells are eukaryotic.