The high luminosity of a Seyfert galaxy____.
a. comes from the halo of the galaxy
b. is distributed through the spiral arms
c. is spread through the central bulge
d. is concentrated in a very small region of the nucleus
e. varies over the course of years
Question 2
The star Betelgeuse appears red; the star Rigel appears blue. What accounts for this difference?
a. Betelgeuse and Rigel have different chemical compositions.
b. Betelgeuse is moving away from Earth, Rigel is moving toward Earth.
c. Betelgeuse is moving toward Earth, Rigel is moving away from Earth.
d. The surface of Betelgeuse is hotter than the surface of Rigel.
e. The surface of Betelgeuse is cooler than the surface of Rigel.