The Exoskeleton Is Often Cited as One of the Reasons

The exoskeleton is often cited as one of the reasons for the success of arthropods.Which of the following concepts related to the exoskeleton would support this hypothesis? Check all that apply.

A) Chitin in the procuticle is tough,yet flexible and contributes to the mechanical protection afforded by the exoskeleton.
B) Sclerotization is one form of hardening of the exoskeleton that results from the chemical crosslinking of proteins.This hardening provides protection,but it also leaves the exoskeleton some resiliency,which is advantageous for activities such as flapping wings and jumping.
C) The procuticle is thickened in the region of joints,which promotes a flexible armor.
D) The epicuticle is impregnated with waxy lipoproteins,which helps prevent water loss and is a barrier to microorganisms.
E) The exoskeleton is modified to form structures that include sensory receptors,modifications that permit gas exchange,and wings (in insects) .