The _______________ of the moon is the period of time for the moon to complete a cycle of the lunar ...

The _______________ of the moon is the period of time for the moon to complete a cycle of the lunar phases and is approximately 29.5 days long.
 
  a. sidereal period
  b. saros cycle
  c. synodic period
  d. eclipse season
  e. umbral period

Question 2

The hydrogen lines in spectral type A stars
 
  a. are most narrow for supergiants.
  b. are most narrow for main sequence stars.
  c. can not be used to estimate the luminosity of the star.
  d. are very weak and difficult to see.
  e. are useful in determining the apparent magnitude of the star.

Question 3

An eclipse season is the period of time during which the
 
  a. moon crosses a node in its orbit.
  b. sun crosses a node in the moon's orbit.
  c. line of nodes crosses the moon's orbit.
  d. the moon is new or full.
  e. the moon is visible during the day.