Why do galaxies have different shapes? a the distance from Earth to each galaxy is different b the mass of the galaxies is different c there are many universes d the gravitational pull between the stars in the galaxies is different

Using simple mechanics its D thats because A wouldn't make sense at all and C wouldn't be related, D might be.

So we're left with B and D. So B is wrong becuase that wouldn't affect the shape it depends on how it was created and how much interaction with other galaxies have made (gravity w / mass). So if you understand Stephen Hawking he said that nature is not perfect and can change. The masses can change and can be collided therefore the answer is:

D