Unit 3: Ecosystems-What Are They? & How Do They Work? 36 cards Lessons: 3.1, 3.2, 3.3, 3.4, and 3.5PATHLIGHT PREPARATORY Unit 3: Ecosystems-What Are They? & How Do They Work? 36 cards Lessons: 3.1, 3.2, 3.3, 3.4, and 3.5