Students should learn that insects are small animals with three body parts (head, thorax, and abdomen), six legs, and usually two antennae. They should also understand that insects live in various places and some can fly. Students should learn that arachnids are a group of animals with eight legs, like spiders and scorpions. Emphasize that they are different from insects (which have six legs). Spiders are a type of arachnid that makes silk and webs, and many arachnids are helpful by eating insects.