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01 The King Penguin 02 Looking Closely at the World 03 On the Rise 04 A Sticky Lesson 05 Review (Lessons 1− 4) 06 Pangaea 07 Jackson’s Chameleon 08 Moving Energy. 09 The Arboreal Tarantula 10 Review (Lessons 6−9) 11 The Keel-billed Toucan 12 Clean Energy 13 The Firefly 14 The Mosquito 15 Review (Lessons 11−14) 16 The Praying Mantis 17 The House Cricket 18 The Brood X Cicada 19 The Boa Constrictor 20 Review (Lessons 16−19) 21 The Great Egret 22 Mold 23 Following a Trail 24 Living in Groups 25 Review (Lessons 21−24) 26 Human Civilization 27 The Black Vulture 28 Common Snapping Turtle 29 Vitamins 30 Review (Lessons 26−29) 31 The Bottom of the Ocean 32 Earthquakes 33 The Andean Condor 34 The Mockingbird. 35 Review (Lessons 31−34) 36 The Great Blue Heron 37 Tiny Pluto. 38 Computer Habits 39 Ruby-throated Hummingbird. 40 Review (Lessons 36−39) 41 The Peregrine Falcon 42 The Atlantic Puffin 43 The Amazon River Dolphin 44 The Names of Stars 45 Review (Lessons 41− 44) 46 Anyone Out There? 47 Fascinating Chimps 48 The Common Loon 49 The Brown Pelican 50 Review (Lessons 46−49)