If Spiral Density Waves Were the Only Thing Producing Spiral

question 18

Multiple Choice

If spiral density waves were the only thing producing spiral arms, what result would be expected?

• A) All spiral arms would be gas-free and dust-free.
• B) All galaxies would have only two smooth spiral arms.
• C) The Milky Way would show an irregular pattern of short arms.
• D) The halo component of the Milky Way would show spiral arms as well.

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