Make learning about the human respiratory system fun and easy. Explore how this system gets oxygen into the body for gas exchange.

College-level introductory biology course focusing on the application of the fundamental principles of human biology. Course topics include genetics, cell biology, molecular biology, disease (infectious agents, inherited diseases and...

Describes the anatomy of a frog's digestive system and how the stages in the process of digestion. A comparison is made with the human digestive system.