Two groups of invertebrates have notably complex brains: arthropods (insects, crustaceans, arachnids, and others), and cephalopods (octopuses, squids, and similar molluscs). The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. Arthropods have a central brain with three divisions and large optical lobes behind each eye for visual processing. Cephalopods such as the octopus and squid have the largest brains of any invertebrates. COUNT 3
QSN1 Which two groups of invertebrates have complex brains? ANS1 arthropods (insects, crustaceans, arachnids, and others), and cephalopods QSN2 Arthropods and cephalopods have brains that come from a pair of what? ANS2 parallel nerve cords QSN3 The invertebrates with the largest brain are what two animals? ANS3 octopus and squid