Acommon rock type found within oceanic crust is called?

Which of the following describes what rocks usually are composed of ,

Which of the following areas has the highest population density?

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.