Could someone please comment on 117 regarding answer D ?
if the density of the "observable universe" (defined in the passage as "luminous matter in the form of galaxies")com[ing] to a small fraction of the[necessary 3 hydrogen atoms/cubic meter] forms the basis for the assertion that "there must be enough INVISIBLE (nonluminous) matter in the universe to exceed the luminous matter by a density by a factor of roughly 70", then wouldn't this density estimate of the observable universe being understated (as
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if the density of the "observable universe" (defined in the passage as "luminous matter in the form of galaxies")com[ing] to a small fraction of the[necessary 3 hydrogen atoms/cubic meter] forms the basis for the assertion that "there must be enough INVISIBLE (nonluminous) matter in the universe to exceed the luminous matter by a density by a factor of roughly 70", then wouldn't this density estimate of the observable universe being understated (as
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