Here's why:

* Organic: Nucleic acids are composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus, making them organic compounds.

* Large and Complex: They are long polymers made up of repeating units called nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

* Store Information: Nucleic acids, specifically DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), store genetic information in a coded form. This code is based on the sequence of the four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA, or uracil (U) in RNA.

Let me know if you'd like more details about DNA or RNA!