What is the difference between the body segments of insects versus the body segments of arachnids?

Insects have three main body segments: the head, thorax, and abdomen, which are distinct and serve different functions such as sensory processing, locomotion, and digestion. In contrast, arachnids have two body segments: the cephalothorax (which combines the head and thorax) and the abdomen. Additionally, insects typically have six legs, while arachnids possess eight legs, reflecting their different evolutionary adaptations.