What can change the expansion rate of the Universe over time? O Gravity: Attractive forces increase the expansion rate by pulling mass together making gravity stronger. O Gravity decreases the expansion rate, while electromagnetic forces are always repulsive and speed-up expansion. O Attractive forces such as gravity decrease the expansion rate. Repulsive forces would speed-up expansion by pushing spacetime apart. O Nothing, since the expansion rate remains always constant, and it is measured from Hubble's law.

What can change the expansion rate of the Universe over time? O Gravity: Attractive forces increase the expansion rate by pulling mass together making gravity stronger. O Gravity decreases the expansion rate, while electromagnetic forces are always repulsive and speed-up expansion. O Attractive forces such as gravity decrease the expansion rate. Repulsive forces would speed-up expansion by pushing spacetime apart. O Nothing, since the expansion rate remains always constant, and it is measured from Hubble's law.