Final answer:
Nucleic acids are composed of long chains of nucleotides and include DNA and RNA, which are vital for storing genetic information and protein synthesis.
Step-by-step explanation:
The molecule that is composed of long chains of nucleic acids is nucleic acid. Nucleic acids, such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are essential biological macromolecules. They consist of long chains of nucleotides, which in turn are made of a sugar, a nitrogen-containing base, and a phosphate group. DNA is the molecule that stores genetic information in the form of a double-stranded helix, while RNA is single-stranded and plays a crucial role in the synthesis of proteins.