Here's why:

* Stores Genetic Information: DNA contains the instructions for building and maintaining an organism. These instructions are encoded in the sequence of its four nucleotide bases (adenine, guanine, cytosine, and thymine).

* Passed Down Through Generations: DNA is passed from parents to offspring, ensuring the transmission of genetic traits.

* Determines Traits: The specific sequence of DNA within an individual's genes determines their physical characteristics, such as eye color, height, and susceptibility to certain diseases.

While DNA is often called the "molecule of life", that's a bit of an oversimplification. It's more accurate to say it's the molecule of heredity because it plays the crucial role in passing genetic information from one generation to the next.