A nucleic acid found in the nucleus carrying the organism's hereditary information is called:

• A. DNA
• B. RNA
• C. Protein
• D. Lipid

Answer: (A)

DNA is the molecule that stores an organism's hereditary information in the nucleus. Its sequence of nucleotides encodes the genes and provides the instructions for building proteins and functional RNAs, and this information is faithfully copied during cell division to pass traits to offspring. In eukaryotic cells, this genetic material is organized into chromosomes within the nucleus, though some heredity-related DNA also exists in organelles like mitochondria. RNA, while essential for reading that code and directing protein synthesis, serves as the intermediary rather than the long-term store of hereditary information. Proteins are the products of gene expression, and lipids are structural or energy-storage molecules, not carriers of genetic information. Therefore, the nucleic acid found in the nucleus carrying the organism's hereditary information is DNA.