Who Messed Up the Treehouse?/Fact or Fiction?

"Who Messed Up the Treehouse?": The kids do a bunch of projects in the treehouse. Sean makes paper airplanes, Jet has a picnic with Sunspot, Sydney makes Commander Cressida comics, and Mindy makes a puppet show. However, they leave a lot of trash there. No one wants to take responsibility for it. They try to find other places to play, but they don't work out. In the end, they learn to share the responsibility and keep the treehouse clean. "Fact or Fiction": Mindy tells Jet that clouds are made out of cotton balls. Jet, of course, believes this, but Sean and Sydney don't. Mindy says she learned this from Lillian. Lillian later clarifies that she thinks clouds are made of cotton candy, which Jet and Mindy also end up believing, much to Sean and Sydney's annoyance. The kids go to Dr. Rafferty and Dr. Skelley, who teach them what clouds are really made of and how to find correct information.