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Select the correct answer. what was edwin hubble's contribution to the field of astronomy? a. he discovered variable stars. b. he proved that the heliocentric model accurately described our solar system. c. he found a relationship between the period luminosity and distance of stars. d. he proved that the universe is finite. e. he discovered that the universe was expanding.

Which of the following is a correct conversion factor? select one: 1 kg = 1,000 g 1,000 m = 1 mm 100 ml = 10 mm 1 l = 100 g

Can you me with this question? i don’t understand.