Here's why:

* Chromatin is the complex of DNA and proteins that makes up chromosomes within the nucleus of eukaryotic cells.

* It exists in a loose, uncoiled form during interphase (the period between cell divisions).

* When a cell prepares to divide, chromatin condenses into the more familiar, tightly packed structures called chromosomes.

So, while DNA is the fundamental molecule, chromatin is the term for the overall structure of DNA and its associated proteins within the nucleus.