Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: The answer depends on if the cell is prokaryotic or eukaryotic. The main difference between the two types of cells is the presence of a nucleus. And in eukaryotic cells, DNA lives in the nucleus. Answer: the presence of a nucleus
A:
What is the main difference between prokaryotic or eukaryotic cells ?