CK-12 Foundation
Ck 12: Principles of Biology
[Free Registration/Login may be required to access all resource tools.] Explains the four principles that unify biology - cell theory, gene theory, homeostasis, and evolution.
CK-12 Foundation
Ck 12: Biology: Principles of Biology
[Free Registration/Login may be required to access all resource tools.] Covers the four unifying principles of biology.
CK-12 Foundation
Ck 12: Biology: Principles of Biology
[Free Registration/Login may be required to access all resource tools.] Covers four unifying principles of biology: cell theory, gene theory, homeostasis, and evolutionary theory.