1. As far as an astronomer is concerned, a metal refersto
A any element
B any element exceptHydrogen
C any element exceptHelium
D any element exceptHydrogen and Helium

2. A spiral density wave refers to a region of enhanced density inthe Galaxy which rotates more slowly than the stars and gas.
A True
B False

3. Globular clusters in the halo of the Milky Way appear to havestars that are younger than open clusters in the disk of the MilkyWay
A True
B False

4. Population I and II stars differ in that
A population I starsare metal-poor and younger than population II stars.
B population I stars aremetal-poor and older than population II stars.
C population I stars aremetal-rich and older than population II stars.
D population I stars aremetal-rich and younger than population II stars.

5. Where are the majority of older, metal-poor stars found in theMilky Way galaxy?
A In globular clustersin the galactic halo.
B Throughout the wholegalaxy.
C In the disk and spiralarms.
D At the galacticcenter.

6. The center of our Milky Way Galaxy can be observed most easilyat which of the following electromagnetic wavelengths?
A Ultravioletradiation.
B Infrared and radiowaves.
C Visible light.
D High-energy gammarays.