DNA's Organizational Units

Steps:

• DNA forms the genetic material in cells, carrying instructions for traits.
• DNA molecules are long chains organized into functional segments.
• These segments, called genes, encode specific proteins or RNA molecules.
• Match the term "sections" to the choice that defines these units.

Why B is correct:

• Genes are defined as specific sequences of nucleotides in DNA that serve as the basic units of heredity, directing cellular functions.

Why the others are wrong:

• A: Chromosomes are coiled structures containing entire DNA molecules, not sections of DNA.
• C: Nuclei are organelles housing DNA, not divisions of DNA itself.
• D: Proteins are molecules produced by DNA instructions, not sections of DNA.

Final answer: B