Here's a breakdown:

* DNA (Deoxyribonucleic acid) is the molecule that contains the genetic instructions for an organism.

* Genes are specific segments of DNA that carry the code for a particular trait. This code determines the production of proteins, which ultimately influence how a trait is expressed.

* Traits are the characteristics or features of an organism. These can range from physical attributes like eye color to more complex things like behavior or susceptibility to certain diseases.

So, genes are the fundamental units of heredity, acting as blueprints for building and maintaining organisms.