Large organic molecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus are primarily nucleic acids.

Here's why:

* Nucleic acids are the building blocks of genetic information and are essential for all life. They are made up of nucleotides, which consist of a sugar molecule (deoxyribose in DNA and ribose in RNA), a phosphate group, and a nitrogenous base.

* DNA (deoxyribonucleic acid) carries the genetic instructions for building and maintaining an organism.

* RNA (ribonucleic acid) plays a crucial role in protein synthesis and other cellular processes.

While other complex molecules contain some of these elements, nucleic acids are uniquely characterized by the presence of phosphorus in their structure, which is crucial for their function.

Let me know if you'd like to learn more about nucleic acids, DNA, or RNA!