Here's why:

* Eukaryotes are organisms whose cells contain a nucleus and other membrane-bound organelles. The nucleus houses the cell's genetic material (DNA).

* Prokaryotes, on the other hand, are organisms whose cells lack a nucleus and other membrane-bound organelles. Their DNA is located in a region called the nucleoid, which is not enclosed by a membrane.

Examples of eukaryotes include animals, plants, fungi, and protists. Examples of prokaryotes include bacteria and archaea.