Spiral arms are regions of star formation, which accounts for their blue color. (True or false?)

Spiral arms are regions of star formation, which accounts for their blue color.
 
  Indicate whether the statement is true or false

Question 2

Which of the following studies is best suited to astronomical observations that fall into the category called timing?
 
  A) studying how different planets differ in their surface compositions
  B) studying how a star's brightness varies over a period of 3 years
  C) measuring the rotation rate of a distant star
  D) determining the age of the solar system

Question 3

Planets found in the habitable zone of other stars
 
  A) are all rocky planets, like the terrestrial planets in our solar system.
  B) are all jovian planets.
  C) include some Earths and super-Earths.
  D) include hot Jupiters.
  E) have been demonstrated to be barren of all life.

Question 4

The critical temperature above which pair production can occur is called the:
 
  A) Chandrasekhar Limit.
  B) Cosmological Constant.
  C) fusion temperature.
  D) threshold temperature.
  E) event horizon.