How are dna and rna molecules alike? a) they are both double stranded. b) they both contain nitrogen bases. c) their nitrogen bases always pair a - t and c - g. d) they are found in the nucleus and at the ribosomes. eliminate

They both contain nitrogenous bases. 
DNA genomes are stable and can grow to much larger sizes (other viruses and all organisms larger than them). They are both nucleic acids. Regarding structure, DNA and RNA are similar because they are both built of nucleotides, structures consisting of one nuclease, a sugar (ribose or deoxyribose respectively) and a phosphate group.

DNA is a double strand, RNA is a single strand. They are both made up of nucleotides. They both have nitrogen bases, but they have one difference. RNA has Uracil instead of Thymine that DNA has. DNA is found in the nucleus and RNA is in cytoplasm. 
 I believe your answer is B.