Most fully-formed galaxies reside in small groups and clusters, where they can interact with other galaxies. These interactions can have major effects on the characteristics of a galaxy. Use the labels to complete the descriptions of how interactions can cause galaxies to evolve over time.

a. A starburst galaxy is characterized by a rapid and intense period of star formation
b. A minor galaxy merger in which a large galaxy consumes a smaller galaxy is calledgalactic cannibalism
c. As two galaxies interact and strip stars from each other, a tidal stream of stars can form
d. When two large galaxies collide, a major merger occurs, turning spirals into ellipticals with no ongoing star formation