Which of the following statements about human DNA is correct?

• A. Human DNA is typically double-stranded and forms a right-handed helix known as B-DNA.
• B. Human DNA contains uracil as one of its four nitrogenous bases.
• C. Human DNA is composed of a single linear molecule in each cell.
• D. The sugar in human DNA is ribose.

Answer: (A)

Verified step by step guidance

1. Review the structure of human DNA, noting that it is composed of two strands forming a double helix.
2. Recall that the common form of DNA in human cells is B-DNA, which is a right-handed helix.
3. Identify the nitrogenous bases in human DNA: adenine (A), thymine (T), cytosine (C), and guanine (G); note that uracil (U) is found in RNA, not DNA.
4. Understand that human DNA is organized into multiple linear chromosomes, not a single linear molecule per cell.
5. Recognize that the sugar in DNA is deoxyribose, whereas ribose is found in RNA.