Which arthropod class typically has three body regions: head, thorax, and abdomen?

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Multiple Choice

Which arthropod class typically has three body regions: head, thorax, and abdomen?

Insects are defined by a three-part body plan: head, thorax, and abdomen. The head houses sensory organs and mouthparts, the thorax bears the legs and, in many species, the wings, and the abdomen contains the digestive and reproductive organs. This clear head–thorax–abdomen organization is a hallmark of insects, setting them apart from other arthropod groups. Diplopoda (millipedes) and Chilopoda (centipedes) have many body segments forming a continuous trunk, not three distinct regions. Arachnids, meanwhile, have two main regions—the cephalothorax and the abdomen—rather than separate head, thorax, and abdomen.

Insects are defined by a three-part body plan: head, thorax, and abdomen. The head houses sensory organs and mouthparts, the thorax bears the legs and, in many species, the wings, and the abdomen contains the digestive and reproductive organs. This clear head–thorax–abdomen organization is a hallmark of insects, setting them apart from other arthropod groups. Diplopoda (millipedes) and Chilopoda (centipedes) have many body segments forming a continuous trunk, not three distinct regions. Arachnids, meanwhile, have two main regions—the cephalothorax and the abdomen—rather than separate head, thorax, and abdomen.

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