What might likely be affected by the existence of “dark matter”?

I believe what might be affected by the existence of dark matter would be the rate at which the universe is expanding.
hope this helps!

Gravity potential and the density and velocity of the matter.

Explanation:

Dark matter is composed of the particles that are not absorbed or reflect the light, and thus cannot be seen directly. About 85 % of the universe is made up of dark matter. The dark matter tends to accumulate energy at its center and candles to the sudden collision or energy burst that occurs in the universe. Thus They lack the efficient means to lose out the energy. And they also lack the needed range for the interaction of the structure formations by the interaction of the atoms and the electrons.

Ihere is the definition of do u want ut