Here's why:

* DNA contains the genetic code: This code acts like a blueprint, providing instructions for building and maintaining the entire organism.

* Genes within DNA: DNA is organized into genes, which are specific segments that code for particular proteins and functions. These proteins perform a wide variety of tasks within the cell.

* Passed down through generations: DNA is replicated and passed down from parent cells to daughter cells, ensuring the continuity of genetic information.

While other cellular components like RNA and proteins play important roles in carrying out the instructions encoded in DNA, DNA itself is the ultimate repository of all the information a cell needs to function and reproduce.