[Campbell Biology P.1182] Which of the following statements accurately distinguishes the grow... | Practice Question
Which of the following statements accurately distinguishes the growth mechanism of a clam's shell from that of an arthropod's cuticle?
A: Both clam shells and arthropod cuticles are shed periodically through molting to allow for growth.
B: Clam shells grow by adding material to the outer edge, while arthropod cuticles are shed (molted) and a larger one is produced.
C: Arthropod cuticles are continuously enlarged from within, whereas clam shells grow by expanding their existing structure.
D: Clam shells are primarily composed of chitin, while arthropod cuticles are calcium carbonate, leading to different growth patterns.
Explanation
The text states that clams 'enlarges its shell by adding to the outer edge,' indicating continuous growth by accretion. In contrast, it explicitly mentions that arthropods 'must shed its exoskeleton molt and produce a larger one' to grow.