How Does the Amount of Dust and Gas in a Spiral

question 140

Multiple Choice

How does the amount of dust and gas in a spiral galaxy vary with the classification of the galaxy?

• A) The most loosely wound galaxy, Sc, has the most dust and gas in its arms.
• B) All spiral galaxies Sa, Sb, and Sc types have about the same fraction of gas and dust within them, about 4% by mass.
• C) Only the most tightly wound spiral galaxies, type Sa, have any dust or gas in them at all.
• D) The most loosely wound galaxy, Sc, has the least dust and gas in its arms.

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