a protein has a molecular weight of 30000g / mol. Calculate the number of nucleotides contained in the gene encoding this protein knowing that 20% are introns. The weight of a nucleotide is 110 g / mol. The weight of an amino acid is 330 g / mol

Are you asking about a street map usage  if so here is your answer  a street map for a very limited area could simply be a bit map or a .jpg image.  but a more general map would probably store the streets as vectors.  but you shouldn't assume that there is one way to do it

Carbon dioxide is the correct answer