The two factors most likely to affect whether a galaxy will evolve by merging with a second galaxy are:
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its size compared to that of the other galaxy - The gravitational effects and dynamics involved in galaxy mergers are significantly influenced by the relative sizes of the galaxies.
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its distance from the other galaxy - The likelihood of a merger occurring decreases with increasing distance; closer galaxies are more likely to interact and merge due to gravitational attraction.
These factors play a critical role in determining the interactions and eventual merging of galaxies.