What are chromosomes?

• A. Structures made of DNA that contain genetic information.
• B. Cytoplasmic organelles responsible for protein synthesis.
• C. Units of inheritance that do not contain DNA.
• D. The cellular structures that store nutrients.

Answer: (A)

Chromosomes are the carriers of genetic information, structures made of DNA wrapped with proteins that package and protect the genetic material. They reside in the nucleus of most cells and carry genes—the specific sequences that determine inherited traits. That makes the description of chromosomes as DNA-containing structures that contain genetic information the best fit. The other ideas describe things not involved in carrying hereditary material: cytoplasmic organelles responsible for protein synthesis (like ribosomes), units of inheritance that do not contain DNA (genes are the DNA sequences that make up inheritance), or structures that store nutrients (different organelles). In short, chromosomes are the DNA-based carriers of heredity.