Arthropods
1. Versatile exoskeleton 2. Segmentation and appendages for more efficient locomotion 3. Air piped directly to cells 4. Highly developed sensory organs.
Phylum Arthropoda “arthro” = jointed “pod” = foot, appendage largest phylum of animals on Earth; 3 of 4 animals are some kind of arthropod chitinous exoskelton.
