CK-12 Foundation
Ck 12: Characteristics of Life
[Free Registration/Login may be required to access all resource tools.] Videos, texts, activities, and assessments about the factors that characterize living things.
CK-12 Foundation
Ck 12: Life Science: Reptiles
[Free Registration/Login may be required to access all resource tools.] What reptiles can you name? Snakes, alligators, and crocodiles are all reptiles. Modern reptiles live on every continent except Antarctica. They range in size from...
CK-12 Foundation
Ck 12: Life Science: Echinoderms
[Free Registration/Login may be required to access all resource tools.] You're probably familiar with starfish and sand dollars. They are both echinoderms. Sea urchins and sea cucumbers are also echinoderms. What's similar between these...