BREEDERS Symbiotic relationships between living things are constantly at work on Earth, from the largest animals to organisms too small to see with the naked eye, "Parasites and Partners look to introduce these unique relationships to readers in grades 5-7. Complex biological concepts, relationships, and life cycles are explained throughout with clear text and accompanying artwork and photographs. Each book will take one broad relationship type and discuss it in an easy-to-understand way within a framework packed with fascinating and often bizarre examples.