Nucleic acids are present in living cells and include DNA and RNA.

• A. They are only found in plants
• B. They are only found in animals
• C. They are not present in cells
• D. They are present in living cells and include DNA and RNA

Answer: (D)

Nucleic acids are the molecules that store and transmit genetic information inside cells. They are present in living cells and include DNA, which stores the genetic blueprint, and RNA, which helps read that blueprint and carry out gene expression. This makes the statement correct because it reflects both the universal presence of nucleic acids in living cells and the two main types, DNA and RNA. The other ideas—nucleic acids being restricted to plants or to animals, or not existing in cells—don’t fit with how biology shows that all living cells contain these essential molecules.