In globular clusters, the brightest stars will be:

In globular clusters, the brightest stars will be:
 
  A) massive blue main sequence stars.
  B) red supergiants.
  C) T Tauri stars.
  D) blue stragglers.
  E) planetary nebulae.

Question 2

Distinguish an Sa from an Sc galaxy.
 
  What will be an ideal response?

Question 3

Which class of stars probably has too small a habitable zone for life to arise?
 
  What will be an ideal response?

Question 4

The lithosphere of a planet is the layer that consists of
 
  A) material above the crust.
  B) material between the crust and the mantle.
  C) the rigid rocky material of the crust and uppermost portion of the mantle.
  D) the softer rocky material of the mantle.
  E) the lava that comes out of volcanoes.