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Q23: Absorption lines due to interstellar gas<br>A)are wider
Q30: A(n) _ is a cool, dense cloud
Q47: What is the ratio of the light-gathering
Q65: A breeze of low-density ionized gas that
Q74: Two white dwarf stars are the same
Q96: _ in Earth's atmosphere absorbs most ultraviolet
Q107: An absorption spectrum is also called a
Q125: Which one of the hydrogen atoms below
Q137: _ made very accurate observations of the
Q144: The _ period (or "month") of the