Final answer:
If all dark matter were removed, galaxy rotation curves would change, gravitational forces between galaxies and the mass of galaxy clusters would decrease, but the expansion rate of the universe would not necessarily increase as it is driven by dark energy.
Step-by-step explanation:
If all the dark matter in our universe were to be instantaneously removed, the following would not happen: the rotation curves of galaxies would remain unchanged. This is because the presence of dark matter significantly impacts the rotation speeds of stars within galaxies, observed through the galaxy rotation curves. Without dark matter, these curves would be different, indicating that the rotation speeds of stars would not be as high without the gravitational effects of dark matter.
Gravitational forces between galaxies would decrease, since dark matter contributes to the overall mass of galaxy clusters, influencing gravitational interactions. Similarly, galaxy clusters would become less massive without dark matter. However, the expansion rate of the universe would not necessarily increase. This expansion is mainly attributed to dark energy, not dark matter. The removal of dark matter would decrease the gravitational pull resisting expansion, but it is dark energy that's driving the accelerated expansion of the universe, and this would not be directly affected by the absence of dark matter.