AP BIOLOGY

Detailed explanation-1: -Proportion of species in the kingdom Animalia, which are arthropods versus all other animals. The vast majority of arthropods are insects. The phylum Arthropoda contains a wide diversity of animals with hard exoskeletons and jointed appendages.

Detailed explanation-2: -Arthropod and vertebrate skeletons are quite distinct from each other. Basically, the vertebrate skeleton is internal (an endoskeleton) while the arthropod skeleton is external (an exoskeleton).

Detailed explanation-3: -The external body skeleton of arthropods is called the exoskeleton. It surrounds the animal and provides support. The bodies of arthropods are often divided into distinct regions called the head, thorax, and abdomen.

Detailed explanation-4: -The outer covering of crustaceans is variously called the integument, cuticle, or exoskeleton. It protects the body and provides attachment sites for muscles. The thickness of the cuticle can vary from a thin, flexible membrane, as in some parasitic copepods, to a massive rigid shell, as in crabs.