Collisions between galaxies: a. can turn elliptical galaxies into spirals. b. are the best explanation for gamma-ray burst events. c. cause large numbers of stars to collide and explode. d. cause the gas and dust clouds to collide, leading to rapid star formation. e. are much rarer than collisions between stars.

d. cause the gas and dust clouds to collide, leading to rapid star formation

Explanation:

When galaxies collide spiral galaxies become elliptical galaxies.

Gamma ray bursts are thought to be caused by Neutron star collisions which are rare. Neutron stars form after a Supernova.

Stars are so far apart in galaxies that collisions of stars rarely occur

The collision of galaxies leads to the starburst cycle of a galaxy.

Galaxies colliding are rarer as they are farther apart than stars.