Spiral Structure

question 47

Multiple Choice

Spiral structure:

• A) rotates at the same speed as the gas in the disk
• B) rotates at a speed that is different than the gas in the disk
• C) stays constant in time as the gas in disk rotates through it
• D) rotates backward compared to the stellar orbits
• E) must only last a short time, since few galaxies with disks show spiral patterns

---

Definitions:

Arteries

Blood vessels that carry oxygenated blood away from the heart to the body's organs and tissues.

Buildup

The gradual accumulation or increase of something over time.

Diastolic Pressure

The pressure in the arteries when the heart rests between beats.

Force

In physics, an interaction that, when unopposed, changes the motion of an object.