The arthropod exoskeleton is made up of:

The arthropod exoskeleton is made up of:

• A. Chitin
• B. Calcium carbonate
• C. Keratin
• D. Collagen

Answer: (A)

Arthropod exoskeletons are built from chitin, a tough, flexible polysaccharide that forms the main scaffold of the cuticle. This chitin framework is often reinforced by proteins and hardened through a process called sclerotization, giving the exoskeleton its strength. In some groups, especially many crustaceans, minerals like calcium carbonate can be deposited to make the shell even stiffer, but the core material remains chitin. Keratin and collagen are major structural materials in vertebrates, not in arthropod cuticles, so they aren’t the primary components of the arthropod exoskeleton.

Arthropod exoskeletons are built from chitin, a tough, flexible polysaccharide that forms the main scaffold of the cuticle. This chitin framework is often reinforced by proteins and hardened through a process called sclerotization, giving the exoskeleton its strength. In some groups, especially many crustaceans, minerals like calcium carbonate can be deposited to make the shell even stiffer, but the core material remains chitin. Keratin and collagen are major structural materials in vertebrates, not in arthropod cuticles, so they aren’t the primary components of the arthropod exoskeleton.