In one experiment 97 undergraduate students learned about plate tectonics from a multimedia presentation involving narrated animations and support in one of four forms. Support in the prompting condition included hints inducing participants to self-explain critical information. The signaling condition included overviews recapping critical information. The questioning condition included questions about critical information and feedback on participants' answers. The control condition included no support. Participants in the questioning condition outperformed those in the rest of conditions in retention and transfer. This means that questioning is a very powerful technique for promoting multimedia learning.