| A | B |
|---|
| pheromone | chemical secreted by an animal species to influence the behavior of other members of the same species |
| Malpighian tubule | the waste-excreting structure that also helps maintain homeostatic water balance in most arthropods |
| spiracle | opening in the arthropod body through which air enters and waste gases leave |
| book lung | the respiratory structure in spiders that consists of highly folded walls with membranes that look like book pages |
| tracheal tubule | respiratory structures that consist of a tube system that branches into smaller tubules and carries oxygen throughout the body |
| mandible | a pair of appendages in the mouthpart of most arthropods that allow for biting and chewing |
| molting | the process of shedding the exoskeleton |
| appendage | structures that grow and extend from an animal’s body |
| cephalothorax | when the thorax region has fused with the head into a single structure |
| abdomen | the posterior body region, consisting of fused body segments |
| thorax | the middle body region, consisting of three fused main segments to which, in many arthropods, the legs and wings are attached |
| ganglion | a group of nerve cell bodies that coordinates messages |
