Chitin is also found in the cell walls of fungi.
The exoskeleton of Arthropods is made up of Chitin.
(A) Hyaluronic Acid - Incorrect: This is a component of animal connective tissue, not exoskeletons.
(B) Chitin - Correct: Arthropod exoskeletons consist of chitin, a nitrogen-containing polysaccharide.
(C) Waxes - Incorrect: While waxes may coat the exoskeleton, they're not its structural component.
(D) Cellulose - Incorrect: This is the plant cell wall component, not found in arthropods.
The correct answer is (B) Chitin, the characteristic tough polysaccharide in arthropod cuticles.
Assertion (A): Circulatory system of arthropods and molluscs is mainly open type.
Reason (R): Blood pumped out by the heart is circulated through a series of blood vessels in them.