What is the structure that contains DNA in living cells?

• A. Nucleus
• B. Chromatin
• C. Chromosomes
• D. Ribosomes

Answer: (C)

The structure that contains DNA in living cells is most accurately identified as the nucleus. The nucleus serves as the cellular compartment where the genetic material is housed and organized within eukaryotic cells. Within the nucleus, DNA is present in a form that is largely uncoiled and combined with proteins, called chromatin. When a cell prepares to divide, the chromatin condenses into structures known as chromosomes, which are the physical carriers of genes.

Although ribosomes are essential cellular machinery for protein synthesis, they do not house DNA. Instead, they interpret the genetic instructions carried by messenger RNA (mRNA) to produce proteins.

In summary, while chromatin and chromosomes are forms of DNA organization within the nucleus, the most complete and encompassing answer to where DNA is contained in living cells is the nucleus itself, as it is the designated storage site for the cell's entire genetic information.