Here's a breakdown:

* Genes: These are the units of heredity, responsible for passing traits from parents to offspring. They are made up of DNA, and each gene contains the instructions for building and maintaining a specific protein.

* Chromosomes: These are structures made of tightly coiled DNA, which are located within the nucleus of a cell. Each chromosome carries a specific set of genes.

* DNA: Deoxyribonucleic acid, the molecule that carries the genetic instructions used in the development and functioning of all known living organisms.

Think of it like this:

* Genes: The words in a book.

* Chromosomes: The pages of the book.

* DNA: The entire book.

So, the chromosomes essentially hold all the information needed to build and maintain an organism, and they pass this information down through generations.