Complex sentence: The Metroparks Zoo has one of the largest collections of primates in North America, and features Monkey Island, a concrete island where a large population of Colobus Monkeys are kept in free-range conditions (without cages or walls).
Split into simpler sentences: The Metroparks Zoo has one of the largest collections of primates in North America. It features Monkey Island, a concrete island where a large population of Colobus Monkeys are kept in free-range conditions (no cages or walls).