Arachnida is a class of joint-legged invertebrates that includes creatures like spiders, scorpions, ticks, and mites. They are characterized by having eight legs, two main body segments, and no antennae. Most arachnids are predators, using specialized mouthparts to capture and consume their prey. They can be found in various habitats, from forests to deserts, and play essential roles in ecosystems. Unlike insects, which have three body segments and six legs, arachnids have unique adaptations that help them thrive. Many species, such as spiders, produce silk for building webs or capturing prey. Some arachnids, like scorpions, are known for their venom, which they use for defense and hunting.