What evidence supports the idea that a collision between two spiral galaxies might lead to the formation of a single elliptical galaxy?

These spiral galaxies after the collision fall into clusters, lose speed, change its morphology and becomes an elliptical galaxy all that confirmed by the fact that each "disk" of the colliding galaxy can be destroyed like that.

Explanation:

The harassment of two spiral galaxies may cause the formation of a single elliptical one. The pieces of evidence were found by simulation, at the beginning of the 1980s by Farouki and Shapiro work. Later confirmed in 1996-8 by Moore et alii. The proximity of these massive galaxies causes loss of amounts, turning the shape of that galaxy, from a spiral to an ellipse.

In short, these spiral galaxies after the collision fall into clusters, lose speed, change its morphology and becomes an elliptical galaxy all that confirmed by the fact that each "disk" of the colliding galaxy can be destroyed like that.

Answer: the evidence that supports the formation of a single elliptical galaxy by collision of spiral galaxies are:

A) at the core of dense clutters of galaxies, elliptical galaxies are populous in the galaxy populations.

B) observations of some elliptical galaxies with stars and gas clouds in their cores that orbit differently from the other stars in the galaxy.

C) observations of shells of stars revolving around elliptical galaxies that may have formed from stars that have been stripped of from smaller galaxies.

D) observations that show that at the center of dense clusters, giant elliptical galaxies may have grown by consuming other galaxies.

Explanation:

Elliptical galaxies contain older stars and less gas. The universe is a violent place, and collisions between galaxies are frequent, hence when two spirals collide, they lose their familiar shape, morphing into the less-structured elliptical galaxies.