Which of the following best describes RNA?

The choice that best describes RNA is that it is a single-stranded nucleic acid involved in protein synthesis. RNA, or ribonucleic acid, is primarily known for its role in various biological processes, especially in the translation of genetic information from DNA into proteins. Unlike DNA, which is typically double-stranded and serves as a long-term storage of genetic information, RNA is usually single-stranded and can take on various forms, such as messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), each playing a critical role in the synthesis of proteins.

In the context of protein synthesis, mRNA conveys the genetic code from DNA to the ribosome, where it is translated into a corresponding polypeptide chain with the help of tRNA, which brings the correct amino acids for assembly.

This understanding of RNA's structure and function clarifies why other options do not apply. The assertion that RNA stores genetic code is misleading, as it is the DNA that primarily serves as the template for genetic storage, while RNA is more involved in expressing that information. The idea of RNA having a double helix structure refers more accurately to DNA; RNA typically does not adopt this form but can have complex three-dimensional structures