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.
Virginia Tech
Virginia Cooperative Extension: 4 H Virtual Farm: Poultry: Virtual Hatch Project
A virtual chicken-hatch project takes students into the world of egg incubation and embryonic development.
CK-12 Foundation
Ck 12: Life Science: 11.67 Female Reproductive System
Understand the development of the female reproductive system.