Final answer:
The nucleus is found in eukaryotic cells, while prokaryotic cells do not have a nucleus.
Step-by-step explanation:
The nucleus is found in eukaryotic cells, whereas prokaryotic cells do not contain a nucleus. Eukaryotic cells are more complex and contain many membrane-bound organelles, including the nucleus, which houses the cell's genetic material. In contrast, prokaryotic cells have their genetic material in the cytoplasm, in a region called the nucleoid.