The true statement is:
DNA has the sugar deoxyribose, while RNA has the sugar ribose.
The other statements are incorrect:
- DNA is double-stranded, while RNA is typically single-stranded.
- Transcription copies DNA to mRNA, while translation converts mRNA into proteins, so the first part of that statement is incorrect.
- Thymine is only present in DNA, while uracil (not cytosine) is present in RNA.