Final answer:
The key structural difference between DNA and RNA is the type of sugar they contain. DNA has deoxyribose sugar, while RNA has ribose sugar, which makes option A the correct answer.
Step-by-step explanation:
The question asks which of the following best describes a structural difference between DNA and RNA. Let's examine the given statements to find the correct answer.
- DNA has deoxyribose sugar, while RNA has ribose sugar.
- DNA has uracil as one of its bases, while RNA has thymine.
- DNA is single-stranded, while RNA is double-stranded.
- DNA contains phosphate groups, while RNA does not.
Statement A correctly points out that DNA has deoxyribose sugar, which is a sugar with one less oxygen atom compared to the ribose sugar in RNA. Statement B is incorrect as DNA contains thymine instead of uracil, which is found in RNA. Statement C is incorrect as it is the other way around; DNA is double-stranded, while RNA is typically single-stranded. Statement D is also incorrect because both DNA and RNA contain phosphate groups.
Therefore, the correct answer is:
a) DNA has deoxyribose sugar, while RNA has ribose sugar.