Crustaceans are characterized by having how many body regions?

Crustaceans are indeed characterized by having three distinct body regions: the head, the thorax, and the abdomen. This organization allows for a specialization of functions among the regions, where the head typically houses sensory organs and the mouthparts for feeding, the thorax often contains limbs that are adapted for locomotion and feeding, and the abdomen generally plays a role in reproduction and locomotion through swimming.

This three-part body plan is a defining feature of crustaceans, differentiating them from other arthropods that may have different body region arrangements. The clear separation of these areas contributes to their efficiency in various environments, and in many crustaceans, the thorax and head can be fused together into a single structure called the cephalothorax. Understanding this anatomical feature is key to studying crustacean biology and taxonomy.