Which class in the phylum Arthropoda is characterized by a body composed of three segments and three pairs of legs?

The class in the phylum Arthropoda characterized by a body composed of three segments and three pairs of legs is the class of insects. Insects have a body structure divided into three main parts: the head, thorax, and abdomen. This specific segmentation is a defining feature of the insect class.

Additionally, each segment of the thorax contains a pair of legs, which results in a total of three pairs of legs for an adult insect. This anatomical structure allows insects to have a variety of adaptations for movement, feeding, and interaction with their environment.

Other classes within the phylum Arthropoda, such as crustaceans and arachnids, have different body structures. Crustaceans typically have multiple segments and can feature varying numbers of legs, while arachnids are characterized by having eight legs and two main body segments. Mollusks, while sometimes confused due to similar habitats, belong to a different phylum altogether and do not share the segmented body structure that is characteristic of arthropods.