The two factors most likely to affect whether a galaxy will evolve by merging with a second galaxy are:
-
its size compared to that of the other galaxy - The gravitational attraction between galaxies is influenced by their sizes (and masses), making this a significant factor in whether they will merge.
-
its distance from the other galaxy - The proximity of galaxies affects their likelihood of merging. If they are too far apart, the gravitational influence will be too weak for a merger to occur.
Thus, the correct answers are:
- its size compared to that of the other galaxy
- its distance from the other galaxy