The formation of a galactic central bulge is believed to ____.
a. be a slow steady process lasting billions of years
b. start after the formation of spiral arms
c. be a violent process which adds mass to the central black hole
d. begin when the central black hole has reached mature size
e. continue throughout the galaxy's life body
Question 2
The _______________ is the amount of energy needed to pull an electron completely away from the nucleus.
Fill in the blank(s) with correct word