The sugar molecule in RNA has one more hydroxyl group than the sugar molecule in DNA
The only correct statement here is the one regarding the types of sugar in the two molecules. RNA stands for "ribonucleic acid," which is a simple way to remember that it contains the sugar ribose. DNA, on the other hand, stands for "deoxyribonucleic acid." Its sugar is deoxyribose, which is identical to ribose except it is missing a hydroxyl (-OH) group on its second carbon. In total, RNA contains three hydroxyl groups, while DNA contains only two.
In RNA, uracil replaces thymine, not guanine. DNA is generally double-stranded and RNA is generally single-stranded (though both can exist in either form). Prokaryotes contain both DNA and RNA. Finally, DNA is transcribed to RNA in most biological organisms, but RNA can be reverse transcribed to DNA by the protein reverse transcriptase, which is found in some viruses.