The flight instructor reported that his student began the transition to flare on a normal, full stop landing. During the flare, the airplane’s nose yawed to the left. The instructor added right rudder to correct; however, the left wing pitched up. The instructor attempted to correct by applying left aileron to level the wings. He encountered resistance from the student’s flight control inputs, and the airplane touched down on the right main gear, putting a side load on it. The instructor announced that he had taken control of the airplane and initiated a go-around. The pitch trim was set to full nose up, and the instructor could not reduce the trim forces since the trim switch was set to the student’s side. The airplane pitched up and out of ground effect, and the right wing stalled and struck the ground, resulting in the nose and left wing also striking the ground. There were no injuries. An inspector with the Federal Aviation Administration examined the wreckage and determined that the damage to the fuselage and both wings was substantial. The flight instructor reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.