CK-12 Foundation
Ck 12: Flex Book Textbooks: Biology Concepts
[Free Registration/Login may be required to access all resource tools.] A complete, web-based, multi-media textbook which serves as a comprehensive overview of Biology concepts.
CK-12 Foundation
Ck 12: Flex Book Textbooks: Life Science Concepts for Middle School
[Free Registration/Login may be required to access all resource tools.] A complete, web-based, multi-media textbook covering a wide variety of Biological science concepts for middle grades.
CK-12 Foundation
Ck 12: Biology for High School
This digital textbook covers core biology concepts and includes interactive features, real-world examples, videos, and study guides.
CK-12 Foundation
Ck 12: Life Science for Middle School
This digital textbook covers core life science concepts and includes interactive features, real-world examples, and videos.