DNA and RNA differ by
DNA stands for deoxyribonucleic acid, while RNA stands for ribonucleic acid. DNA, thus, carries a deoxyribose sugar and RNA contains a ribose sugar.DNA is composed of several types of nitrogenous bases: adenine, thymine, cytosine and guanine. RNA contains nitrogenous bases similar to DNA, but does not contain thymine. It contains uracil instead.Both DNA and RNA are sugars that are linked to a nitrogen compound at one end and a phosphorus group at the other. However, DNA generally consists of two strands bound together to form a double helix. RNA is typically single-stranded.
So,the correct option is 'A'.