suppose a collision strips gas out of a spiral galaxy. why would this tend to change the spiral galaxy into an elliptical galaxy?

Iwas going to ask that quesytion  sorry dude i dont  know : (    : /

Answerit increases at a steady rate;

Answerthe global climate during the paleogene departed from the hot and humid conditions of the late mesozoic era and began a cooling and drying trend which dispite having been periodically disrupted by warm periods such as the paleocene-eocene thermal maximum, persists today;