Here's a breakdown:

* Genes: Units of heredity that determine specific traits. They are made up of DNA (deoxyribonucleic acid).

* DNA: A long, complex molecule that carries genetic instructions.

* Chromosomes: Tightly coiled strands of DNA found within the nucleus of a cell. Each chromosome contains multiple genes.

Think of it like this:

* Library: Represents a cell.

* Books: Represent chromosomes.

* Chapters: Represent genes.

Each chapter in a book contains information, just as each gene on a chromosome contains instructions for a specific trait.