Here's why:

* Eukaryotic cells are complex cells that have membrane-bound organelles, including a nucleus. These include cells found in plants, animals, fungi, and protists.

* Prokaryotic cells (like bacteria and archaea) are simpler and lack a nucleus. Their genetic material is located in a region called the nucleoid, but it's not enclosed within a membrane.

So, to answer your question directly, any cell that is eukaryotic will contain a nucleus.