DNA is considered the genetic material in most organisms. Which statement best answers the question, “Is DNA found in all living or once-living cells?”

• A. Yes—DNA is found in all living cells and in most once-living cells, although some specialized living cells (e.g., mature mammalian red blood cells) lack DNA.
• B. No—DNA is found only in cells that have a nucleus, so cells without nuclei never contain DNA.
• C. No—DNA is found only in eukaryotic cells; prokaryotic cells do not contain DNA.
• D. Yes—DNA is found in all living cells without exception.

Answer: (A)