Question

Which best describes the present-day universe?

opaque, expanding very slowly, stars produce heavy elements
transparent, expanding at an accelerated rate, stars produce heavy elements
opaque, expanding at an accelerated rate, stars produce only hydrogen and helium
transparent, expanding very slowly, stars produce only hydrogen and helium

Answer 1

transparent, expanding at an accelerated rate, stars produce heavy elements

Explanation: after recombination the universe is largely transparent; observations show the expansion is currently accelerating (dark energy); and stars and supernovae synthesize elements heavier than hydrogen and helium.