| A | B |
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| Arthropod | An invertebrate that has an external skeleton, a segmented body, and jointed appendages. |
| Molting | The process of shedding an outgrown exoskeleton. |
| Crustacean | An arthropod that has two or three body sections, five or more pairs of legs, and two pairs of antennae. |
| Arachnid | An arthropod with two body sections, four pairs of legs, and no antennae. |
| Exoskeleton | A waxy, waterproof outer shell or outer skeleton that protects the animal and helps prevent evaporation of water. |
| Antenna | An appendage on the head of an animal that contains sense organs. |
| Metamorphosis | A process in which an animal’s body undergoes dramatic changes in form during its life cycle. |
| Abdomen | The hind section of an arthropod’s body that contains its reproductive organs and part of its digestive tract. |
| Insect | An arthropod with three body sections, six legs, one pair of antennae, and usually one or two pairs of wings. |
| Thorax | An insect’s midsection, to which its wings and legs are attached. |
| Complete metamorphosis | A type of metamorphosis characterized by four dramatically different stages. |
| Pupa | The third stage of complete metamorphosis, in which an insect changes from a larva to an adult. |
| Gradual metamorphosis | A type of metamorphosis in which an egg hatches into a nymph that resembles an adult, and which has no distinct larval stage. |
| Nymph | A stage of gradual metamorphosis that usually resembles the adult insect. |
