Final answer:
Pill bugs have three body regions: the head, thorax, and abdomen. Their exoskeleton is made up of multiple layers and must be shed to allow for growth during molting.
Step-by-step explanation:
The pill bugs, also known as Armadillidium, are terrestrial crustaceans that have a body divided into three distinct regions. These regions are:
- The head, which contains sensory appendages such as antennae and eyes.
- The thorax, to which the legs are attached. Typically, pill bugs have six legs.
- The abdomen, which houses most of the digestive, respiratory, excretory, and reproductive structures.
Pill bugs belong to the larger group of arthropods, and like other arthropods, they have a hard exoskeleton that provides support and protection but must be shed during the process of molting to allow for growth. The exoskeleton consists of several layers of cuticle, including the exocuticle and endocuticle, with the exocuticle being thin and water-resistant.