An intact blood brain barrier (BBB) is vital to the development and function of the brain. It controls the exchange of materials between the circulatory system and the brain. Which choice represents the main conclusions from this study

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