1. DNA has proof reading ability, but RNA does not. What does proof reading mean? 2. Ribosomes are assembled by the nucleolus. Here the word "assembled" doesn't mean "put together". right? Each subunit of ribosomes is made in nucleolus, and two subunits are put together in cytoplasm when the protein synthesizes. Am I right? 3. Do both prokaryotes and eukaryotes have cytoskeleton? In Kaplan, prokaryotes, don't have cytoskeleton. In DAT destroyer, both have cytoskeleton. In Wikipedia, "it was once thought this structure was unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton." How can I answer in the test if I am confused with two answer choices.