Answer: The correct answer is : The critical density for the universe is approximately 10 ^ -26 kg / m ^ 3 or you can also say 10 hydrogen atoms per cubic meter.
Explanation: This value is given by:
critical density = 3H ^ 2/2 Pi G, where H is the Hubble constant and G is Newton's gravitational constant.
Critical density is the average density of matter necessary for the universe to stop its expansion but after an infinite time.
