1. The Magellanic clouds are
A irregulargalaxies.
B spiralgalaxies.
C ellipticalgalaxies.
D globular clusters.

2. How does the density wave model of spiral arms explain that they are brighter than the areas between the arms?
A There are more starsper unit volume in the arms than in between.
B Brighter stars are in thespiral arms because they follow along with the arms as theymove.
C Brighter stars are in thespiral arms because they are formed there and areshort-lived.
D This part of the model isnot well understood.

3. The Milky Way is an example of which type of galaxy?
A Elliptical.
B Spiral.
C Irregular.
D Lenticular, S0type.

4. What does a spiral galaxy look like when seenedge-on?
A A thick, flat linewith a bulge in the center.
B Round but without spiralarms because they are hidden.
C A thick, flatline.
D A thick line curved intoa spiral shape.

5. What is an SBc galaxy?
A A galaxy with alarge nuclear bulge, and tightly wound arms starting from a barthrough the nuclear bulge.
B A galaxy with a smallnuclear bulge and loosely wound arms coming from the nuclearbulge.
C A galaxy with a smallnuclear bulge, and loosely wound arms starting from a bar throughthe nuclear bulge.
D A galaxy with a moderatenuclear bulge, moderately wound arms, and a bright core.

6. What is the name given to a galaxy with a large nuclear bulge,and tightly wound arms starting from a bar through the nuclearbulge?
A Sb
B Sa
C SBa
D SBc