Besides the spines, what is another component of the stickleback armor?

• A. A thick layer of skin with scales
• B. A hard beak
• C. A row of plates on each side of the body
• D. A bony exoskeleton

Answer: (D)

The armor of a stickleback includes protective spines plus a row of bony plates that run along each side of the body. These plates are dermal bone embedded in the skin and positioned in lateral rows, creating a shield that helps fend off predators while still allowing the fish to move. This is different from simply having a thick layer of skin with scales or from a beak, and it isn’t an external shell like an exoskeleton—the plates are bone associated with the skin and lie along the sides of the body to form the characteristic armored look.