During a hot and humid day, large and dense clouds known as cumulonimbus clouds form. in many cases these clouds will result in a) hurricanes b) snowstorms c) thunderstorms d) pleasant weather

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