Complete the following sentences:1. The circular but relatively flat portion of the galaxy is the ______. 2. The first portion of the galaxy to form was the . 3. A tightly packed group of a few hundred thousand very old stars is a _. 4. A stands out in a photo of a galaxy because it shines brightly with light from massive young stars and glowing clouds of gas and dust. 5. Our Milky Way galaxy is a_ . 6. Stars orbiting in the ___ near the galaxy's center can have orbits highly inclined to the galactic plane.

1. In Spiral or Lenticular galaxies, the galactic disk is the flat portion that consists of 2 components; the stellar component and the gaseous component. The stellar component consists of the galaxy stars while the gaseous component consists of cool gas and dust.

2. The galactic halo is the first portion of the galaxy to be formed. Formation of halos is caused by increased gravitational effects and the presence of primordial black holes. When baryonic and dark matter merges, halos are formed.

3. A globular cluster is a large compact spherical star cluster, typically of old stars in the outer regions of a galaxy.

4. Spiral arms are region of a large concentration of stars in a spiral galaxy. This large concentration of stars are usually very bright and easily noticeable.

5. The Milky Way galaxy consists of flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. The spiral arm that I explained above extends from the center of spiral galaxies. This extension makes it resemble a spiral and thus give spiral galaxies their name.

6. The bulge is a large concentration of stars.