Answer:
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.
