v. 1. Acid rain - bacteria -- v. 2. Bats - cave life -- v. 3. Cells - digestive systems -- v. 4. Dinosaurs - extinction -- v. 5. Eyes - growth -- v. 6. Habitats - lungs -- v. 7. Lymphatic systems - organisms -- v. 8. Oxygen - reptiles -- v. 9. Respiratory systems - stress -- v. 10. Suburban habitats - zoos and aquariums -- v. 11. Index volume.