What evidence supports the idea that a collision between two spiral galaxies might lead to the formation of a single elliptical galaxy?
A)the fact that elliptical galaxies dominate the galaxy populations at the cores of dense clusters of galaxies
B)observations of giant elliptical galaxies at the center of dense clusters that may have grown by consuming other galaxies
C)observations of some elliptical galaxies with stars and gas clouds in their cores that orbit differently from the other stars in the galaxy
D)observations of some elliptical galaxies surrounded by shells of stars that probably formed from stars stripped out of smaller galaxies
E)all of the above

Question

Quizplus · Accepted Answer

All of the given evidence supports the idea that a collision between two spiral galaxies might lead to the formation of a single elliptical galaxy. 
A) The dominance of elliptical galaxies at the cores of dense clusters suggests that they may have formed from mergers of multiple galaxies. 
B) Observations of giant elliptical galaxies at the center of dense clusters that have consumed other galaxies also support this idea. 
C) The different orbital patterns of stars and gas clouds within some elliptical galaxies suggest that they may have formed from the collision of multiple galaxies. 
D) The presence of shells of stars around some elliptical galaxies provides further evidence for the idea that they grew through mergers with smaller galaxies.

What Evidence Supports the Idea That a Collision Between Two