Here's why:

* Nucleus: The nucleus is the control center of the cell, containing the cell's genetic material.

* Chromosomes: Chromosomes are made up of DNA, which carries the instructions for building and maintaining an organism.

* Location: The DNA that makes up chromosomes is tightly packaged within the nucleus.

Think of the nucleus as a safe, and the chromosomes as the precious blueprints inside. They're kept safe and secure in the nucleus.