Question

collisions betweens galaxies are relatively while collisions between stars are relatively common, rare.

Explanation:

Galaxies are large - scale structures with vast distances between stars within them. Due to their large size and proximity in the universe, galaxy - galaxy collisions are more likely to occur. Stars, on the other hand, are much smaller in size relative to the distances between them, making star - star collisions rare.

Answer:

common, rare