1- Assume if you isolate a single nucleotide from a nucleic acid chain and determine that the nitrogenous ring structure is cytosine, you could say with certainty that the nucleotide could have come from:

– DNA but not RNA.
– RNA but not DNA.
– either DNA or RNA.
– neither DNA nor RNA.
– double-stranded DNA but not single-stranded DNA.
2- Which one of the following biological polymers is defined by a physical property rather than a chemical structure?
– proteins
– lipids
– monosaccharides
– nucleic acids
– polysaccharides