(3) Uracil Explanation: DNA (Deoxyribonucleic acid) contains 2-cleoxy-ribose sugar. It contains cytosine and thymine as pyrimidine bases and guanine and adenine as purine bases. RNA (Ribonucleic acid) contains ribose sugar. It contains cytosine and uracil as pyrimidine bases and guanine and adenine as purine bases.