Here are some examples of organisms that have eukaryotic cells:

* Animals: All animals, from humans to insects to sponges, have eukaryotic cells.

* Plants: All plants, from trees to flowers to algae, have eukaryotic cells.

* Fungi: Mushrooms, yeasts, and molds are all made up of eukaryotic cells.

* Protists: This diverse group includes organisms like amoebas, paramecia, and slime molds.

The nucleus is a key characteristic of eukaryotic cells. It contains the cell's genetic material (DNA) and is responsible for controlling and regulating cellular activities.

In contrast, prokaryotic cells (like bacteria and archaea) do not have a nucleus. Their DNA is located in a region called the nucleoid, but it is not enclosed within a membrane.