A complex, nitrogen-containing polysaccharide forms the exoskeleton of arthropods. Which of the following correctly identifies both its monomeric unit and the nature of this polymer?

Step-by-step solution

The exoskeleton of arthropods is made of a complex polysaccharide called chitin. Chitin is a nitrogen-containing polysaccharide composed of N-acetyl glucosamine monomers. According to NCERT, complex polysaccharides like chitin are mostly homopolymers, meaning they are built from the repetition of a single type of monomeric unit. Option 2 is incorrect because chitin is not a heteropolymer. Option 3 is incorrect because the monomer is specifically N-acetyl glucosamine, not just glucosamine. Option 4 is incorrect as N