The Milky Way and other spiral galaxies ____. a. must have ...

[charchew]

The Milky Way and other spiral galaxies ____.
 
  a. must have formed recently, because they contain young stars
 b. formed spiral arms as the result of major collisions with other galaxies
  c. created their disks through the process of galactic cannibalism
 d. must be very old because they contain so much gas and dust
 e. cannot maintain their disk structure if they suffer a major collision

Question 2

A optical distortion of refracting telescopes called _______________ causes a separation of colors, such as when you focus on one color, the other colors in an image are blurred.
 
  Fill in the blank(s) with correct word

[bitingbit]

Answer to Question 1

e

Answer to Question 2

chromatic aberration

[charchew]

YES! Correct, THANKS for helping me on my review

[peter]

Thanks for the timely response, appreciate it