Which feature distinguishes RNA from DNA?

The distinguishing feature that sets RNA apart from DNA is that RNA contains the base uracil. In DNA, thymine is present as one of the nitrogenous bases, while in RNA, uracil takes its place. This difference in nucleotide composition is significant and plays a crucial role in how genetic information is processed in living organisms. The presence of uracil rather than thymine contributes to the overall structural differences between RNA and DNA, including their stability and function.

The other options mention characteristics that are either incorrect or are true for DNA rather than RNA. RNA is typically single-stranded, not double-stranded, and it contains ribose sugar rather than deoxyribose. Additionally, RNA is capable of being synthesized in cells, particularly during the transcription process, where RNA is formed based on a DNA template. Thus, the presence of uracil is the unique feature that clearly differentiates RNA from DNA.