An earthworm (annelida) and a beetle (arthropoda), both have segmented bodies but the beetle has a hard external skeleton. How does the beetle's external skeleton help it survive? [Pg. No. 242]

The beetle's hard external skeleton, called an exoskeleton, helps it survive by protecting its soft internal body parts from injury and predators. It also gives the body proper shape and support, provides points for muscle attachment, and helps in movement through jointed appendages. Since the exoskeleton is made of chitin and is relatively waterproof, it also reduces water loss, allowing beetles to live successfully in drier land habitats compared to animals like earthworms, which have softer and more moist bodies.