Progress AP Biology Complete & Continue Next Lesson Learn More Unit 1: Chemistry of Life 5 Lessons Crash Course Review Review Review Review & Practice Unit 2: Cell Structure and Function 5 Lessons Crash Course Review Review Review Review & Practice Unit 3: Cellular Energetics 4 Lessons Crash Course Review Review Review Unit 4: Cell Communication and Cell Cycle 5 Lessons Crash Course Review Review Review Review & Practice Unit 5: Heredity 6 Lessons Crash Course Review Review Review Practice Problems Chi Square Practice Unit 6: Gene Expression and Regulation 5 Lessons Crash Course Review Review Review Review & Practice Unit 7: Natural Selection 4 Lessons Crash Course Review Review Review & Practice Unit 8: Ecology 5 Lessons Crash Course Review Exponential & Logistic Growth Population Ecology Practice Problems AP Biology Complete & Continue Next Lesson Learn More Unit 5: Heredity Crash Course