3. the amazon river is deep and wide enough to be but it’s seldom used by large commercial ships because it flows through few cities. a. impassable b. navigable c. charted d. developed

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.