1. Dance is like sculpture in that it is based in creating three dimensional shapes in space that affect the emotions of the watcher. These motions are both fluid and static. The fluid motions can be compared to sculptures that are like mobiles and the static motions in which the dancers hold their position are nothing less than living sculpted forms.
2. Tragedies, classically, result in "unhappy endings", in which the primary character dies or suffers a great loss. Traditionally, tragedies have characters of great stature: princes, kings, renowned warriors, who end up badly because of some failing within them (usually referred to as "hubris). Comedies, on the other hand require "happy endings". They are built around confusion, misunderstandings, and almost always matters of the heart.
The happy endings are the result of clarification and reconciliation. That is, the misunderstandings have been fixed and the characters in love have made up. One difference between most traditional tragedies and comedies is that commoners and ordinary people are much more likely to have a major role in a comedy.