1. What are the most massive galaxies in the universe? a. normal spirals, b. barred spirals, c. giant ellipticals d. dwarf ellipticals, e. irregulars 2. Spiral density waves are directly responsible...

1. What are the most massive galaxies in the universe? a. normal spirals, b. barred spirals, c. giant ellipticals d. dwarf ellipticals, e. irregulars

2. Spiral density waves are directly responsible for which of the following? a. flocculent spirals, b. granddesign spirals, c. supernovae, d. the collisions between galaxies, e. galactic cannibalism