Here's why:

* Genome: The complete set of genetic instructions for an organism, contained within the DNA (or RNA for some viruses).

* Chromosomes: Long, thread-like structures made of DNA that are found in the nucleus of most cells. Each chromosome contains many genes.

* Genes: Segments of DNA that contain the code for a specific protein or RNA molecule.

* Nucleus: The control center of a cell, where DNA is stored.

So, all the DNA in each cell body is the entire collection of genetic information, which is called the genome.