Explanation

Arthropods have bodies divided into distinct segments that you can see from the outside. Insects have three main segments: head, thorax, and abdomen. Spiders have two segments while centipedes have many repeating segments along their bodies.

This phylum includes insects, spiders, crabs, and centipedes. They all share segmented bodies, jointed legs, and hard external skeletons called exoskeletons. Arthropods are the largest group of animals on Earth with over a million known species.

Arthropods have bilateral symmetry, not radial symmetry like starfish. They have an open circulatory system where blood flows freely around organs. Their exoskeleton is made of chitin, not bone, and sits outside the body unlike internal endoskeletons.