Wyoming Pesticide Applicator Certification Practice Test

Arthropods are invertebrates that have an exoskeleton, a hard outer shell that provides protection and support for their bodies. This exoskeleton is made of a tough material called chitin and it does not grow with the organism. Because of this, arthropods must molt, or shed, their exoskeleton multiple times in their lifetime in order to grow. This molted body covering is a characteristic of arthropods and is not found in other invertebrate groups. While options B, C, and D may be common characteristics of some arthropods, they are not defining features of the entire group. For example, not all arthropods have wings (some have legs for walking, while others have specialized structures for swimming or jumping), not all arthropods have three body regions (some have only two, such as spiders), and not all arthropods have two pairs of legs (some may have more or less). Thus, these options are not as accurate and specific as option A.