While we often think of spiders as insects, they are actually part of a distinct family. Spiders,
along with scorpions, ticks, and mites, are part of a group of animals called arachnids. Spiders
differ from insects in several ways. First, they have eight legs and two body segments, while
insects have six legs and three body segments. Spiders have simple eyes, while insects have
compound eyes. Most insects have wings; spiders do not. While not all spiders spin webs, all
spiders can make silk thread. This is another way in which they differ from insects.
1. What is the central idea of this paragraph?