How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope? how much greater is the light-collecting area of a 6- telescope than a 3- telescope?
a) two times
b) four times
c) six times

Which statement is the best definition of an atom? a) anything that has mass and occupies space. b) the smallest particle that has the properties of an element. c) a substance that cannot be broken down chemically into simpler substances. eliminate d) the smallest unit of a substance that exhibits all of the properties characteristic of that substance.