What is a defining characteristic of insects?

A defining characteristic of insects is that they possess six legs and three body regions, which include the head, thorax, and abdomen. This anatomical structure is a key factor that sets insects apart from other arthropods. The three body regions are distinct, with the head housing sensory organs and mouthparts, the thorax supporting the legs and, often, wings, and the abdomen containing the reproductive and digestive systems.

Insects are classified under the class Insecta within the phylum Arthropoda, and their unique segmentation is essential for their mobility and functionality. The six legs allow for varied movement and adaptation to diverse environments. Understanding this characteristic is crucial for identifying insects and differentiating them from other arthropod classes, such as arachnids, which typically have eight legs and two body regions.