Describe four ways you could increase the rate of a chemical reaction.

Which of these conditions most likely produces an unstable isotope?

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

Can someone me out on this question for my national 5 chemistry homework