Which two classes of objects were critical to the Shapley-Curtiss ...

[corkyiscool3328]

Which two classes of objects were critical to the Shapley-Curtiss Debate of 1920?
 
  A) white dwarfs and red giants
  B) open clusters and emission nebulae
  C) globular clusters and spiral nebulae
  D) emission nebulae and spiral nebulae
  E) planetary nebulae and white dwarfs

Question 2

All wavelengths of light travel at the same speed in a vacuum, and carry the same energy per photon.
 
  Indicate whether the statement is true or false

[InfiniteSteez]

Answer to Question 1

C

Answer to Question 2

FALSE

[corkyiscool3328]

YES! Correct, THANKS for helping me on my review

[elyse44]

Thanks for the timely response, appreciate it