| A | B |
|---|
| mollusks | Invertebrates with unsegmented bodies that are often protected by hard outer shells. |
| mantle | A thin layer of tissue that covers mollusks internal organs. |
| kidneys | Organs that remove the wastes produced by an animals cells. |
| gills | Organs that remove oxygen from the water. |
| radula | A flexible ribbon of tiny teeth |
| gastropod | The largest group of mollusks, includes snails and slugs, that have a single shell or no shell. |
| bivalve | Group of Mollusks that have two shells held together by hinges and strong muscles, includes clams, oysters, scallops and mussels. |
| cephalopod | Group of mollusks whose feed are adapted to form tentacles around their mouths |
| arthropod | An invertebrate that has an external skeleton, segmented body and jointed appendages. |
| exoskeleton | Outer skeleton that protects the animals and helps prevent evaporation. |
| chitin | Polymer that exoskeletons are made of. |
| molting | The process of shedding an outgrown skeleton. |
| antenna | An appendage on the head that contains sense organs. |
| crustacean | The only arthropods with two pairs of antennae. |
| metamorphosis | A process in which an animals body undergoes dramatic changes in form during its life cycle. |
| arachnid | An arthropod with 2 body sections, 8 legs and no antennae |
| abdomen | Hind section that contains an arachnids reproductive organs and part of its digestive track. |
| insect | Arthropods with three body sections, six legs, one pair of antennae, and usually one or two pairs of wings |
| gradual metamorphosis | Has no distinctly different larval stage |
| complete metamorphosis | Four dramatically different stages, egg, larva, pupa and adult |
| camouflage | Protective coloration in which the insect blends with its surroundings so perfectly that it is nearly invisible to a predator. |
| thorax | The mid-section to which wings and legs are attached |
| pupa | Second stage of complete metamorphosis on which the insect is enclosed in a protective covering and gradually changes from a larva to an adult. |
| nymph | Stage that an egg hatches into in gradual metamorphosis which often resembles the adult insect. |
| echinoderm | An radially symmetrical invertebrate that lives on the ocean floor. |
| water vascular system | Internal fluid system of echinoderms |
| endoskeleton | Spiny internal skeleton |
