Core:
List the chemical elements that make up carbohydrates, fats and proteins

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

The category is the thing that is most simmilar throughout a period