Vary in the number of neutrons but Sama in the number if protons are called isotopes
a nitrogenous base, a sugar, and a phosphate. A nucleotide is the basic subunit of both DNA bad RNA. It contains a base with nitrogen, a 5-carbon sugar and a phosphate group.
...The origin of life on Earth is a set of paradoxes. In order for life to have gotten started, there must have been a genetic molecule.. something like DNA or RNA—capable of passing along blueprints for making proteins, the workhorse molecules of life.