On the galápagos islands, darwin observes tortoises with domed and saddle-shaped shells. how did darwin’s observations of these tortoises with form the theory of evolution by natural selection?

The short-term effect of tar on the body is increased blood pressure.

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