Several summaries here.
Tension in a story or play is built by means of the conflicts. Near the beginning, is the major conflict -- the one that sets the whole story in motion. Then there's the "rising action" part of any story (or play) in which the tension is built by further conflicts and reactions until the tension breaks (climax) and the problem (conflict) is solved.
Reread Act Two with these ideas in mind, and see what you decide. Make a list of conflict, action, reaction, etc. as you go. It should be obvious once you know what you're looking for.