Unit 1 Why Do Wasps Have Stingers? Unit 2 Where Did Unicorns Come From? Unit 3 Changes in the Camera Unit 4 A Race for the Calendar Unit 5 Alien Island Unit 6 What Is a Black Hole? Unit 7 Music Therapy Unit 8 How to Play Dodge Ball Unit 9 Aphrodite of Milos Unit 10 A Gift of Kimchi Unit 11 Moving to Silicon Valley Unit 12 Democracy in Ancient Athens Unit 13 Habitat for Humanity Unit 14 The Discovery of Infrared Unit 15 Staying out of Trouble with Baseball Unit 16 The Emergency of the Disappearing Honeybees