Howard Hughes Medical Institute
Hhmi: Bio Interactive
Explore careers in biological science. This site is run by Howard Hughes Medical Institute and includes many types of virtual laboratories, animations, virtual exhibits, and interactive activities.
American Museum of Natural History
American Museum of Natural History: O Logy: Ask a Scientist
A browsable collection of environment-related questions posed by elementary- and middle-school students to the scientists of the American Museum of Natural History in honor of Earth Day. Great questions and great answers.
Howard Hughes Medical Institute
Hhmi: Ask a Scientist
Ask questions about any topic in biology and receive an e-mail response within two weeks. There is an archive of "Top 10 Questions" and responses for each of the following topics: animals, human biology, general biology, evolution,...
Other
Arm Program's Education Center: Global Warming
An all purpose site with something for everyone. Learn about global warming and climate change, ask a scientist, take a quiz, or get a lesson plan!