In arthropods, molting is necessary because __________.

• A. arthropod appendages generally increase in number as the animal ages
• B. the environment degrades the exoskeleton, which therefore must be shed and replaced
• C. worn exoskeletons make arthropods more susceptible to predators
• D. the exoskeleton is progressively reabsorbed by body tissue
• E. the chitinous exoskeleton cannot grow