Match the terms in the left-hand column to the appropriate blank in the sentences in the right-hand column. Use each term only once.
1. The globular cluster M13 belongs to the halo component of the Milky Way Galaxy.
2. A(n) elliptical galaxy contains hot, ionized gas but very little cool gas or dust.
3. The type of galaxy known as a(n) irregular galaxy was more common in the universe 10 billion years ago.
4. The Milky Way is a(n) spiral galaxy.
5. Our Sun belongs to the disk component of the Milky Way Galaxy.
6. Scientists investigating cosmology study how the distribution of galaxies changes with time.