The chitinous exoskeleton of arthropods is formed by the polymerization of?

1. Keratine sulphate and chondroitin sulphate

2. D-glucosamine

3. N-acetyl glucosamine

4. Lipoglycans

Macro molecule chitin is:

1. Phosphorus containing saccharide

2. Sulphur containing polysaccharide

3. Simple polysaccharide

4. Nitrogen-containing polysaccharide