Virginia Tech
Virginia Polytechnic Institute: Greenhouse Dinosaur Extinction Theory
This comprehensive page discusses the Asteroid Impact vs. Volcano-Greenhouse dinosaur extinction debate. It was written by paleontologist, professor, and scientist Dr. Dewey McLean.
McGraw Hill
Glencoe Biology: Mammal Characteristics: Self Check Quiz
Try these five multiple-choice questions about mammal characteristics. After submitting answers, students can review the material.