Teachers: Have you and your students ever come upon a question with no easy, well-defined answer. If so, then this site from Arizona State University is for you. Intended for K-12 teachers, users can submit a question and, within three days, receive an answer. Also helpful are the Experiments and Stuff, Articles and Profiles, and Web Links sections. The site's guidelines section stresses that the scientists who answer questions for Ask a Biologist are volunteers, but most are acting scientists. Due to volume of questions, or how busy a given scientist is, response time may be a bit slower than the promised three days. A great resource though for those times when you'd like an explanation from an expert and you don't have one handy.