1.) The difference in the brightness of two stars with the same surface temperature is attributable to their _____.


colors


densities


ages


sizes


2.) Most responsible for the formation of a star is _____ force.


electromagnetic


gravitational


interstellar


nuclear


3.)Which main-sequence stars are the most massive?


yellow


orange


red


blue


4.) A spinning neutron star that appears to give off radio wave pulses is called a _____.


supernova


white dwarf


pulsar


black hole


5.) Greater redshifts in the spectra of galaxies indicate _____.


faster speeds


lower temperatures


slower speeds


higher temperatures