1. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms.
2.Arachnids have four pairs of legs, specialized appendages, and a fused head and thorax.
Arachnids include spiders, daddy-long-legs, scorpions, and ticks.
