Which of these is a difference between a DNA and an RNA molecule?

Question: Which of these is a difference between a DNA and an RNA molecule?

1. DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars.
2. DNA is usually double-stranded, whereas RNA is usually single-stranded.
3. DNA contains nitrogenous bases, whereas RNA contains phosphate groups.
4. DNA contains uracil, whereas RNA contains thymine.
5. DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids.

Answer and Explanation