Nucleic acid responsible for carrying out the hereditary program transmitted by an organism's DNA.

• A. Ribonucleic acid
• B. Deoxyribonucleic acid
• C. Nucleic acid
• D. Protein

Answer: (A)

Genetic information is stored in DNA, but to be read and used, a working copy must carry that program to the protein-making machinery. Messenger RNA does exactly that: it transcribes the code from DNA in the nucleus and transports it to ribosomes in the cytoplasm, where the code is translated into a specific sequence of amino acids to build proteins. So, the nucleic acid that carries out the hereditary program is RNA, serving as the interpreter and courier between the genetic storage and the manufacturing of cellular components. DNA stays as the stable storage of information, while proteins are the functional products, not nucleic acids. A blanket term like nucleic acid is too vague when the question is asking for the molecule that actively carries out the program.