Final answer:
The cuticle plus endocysts refers to the exoskeleton of an arthropod, which is a protective layer vital for its growth and protection.
Step-by-step explanation:
The cuticle, also known as the ectocyst, combined with endocysts refers to the layered structure that makes up the exoskeleton of an arthropod. The cuticle is a protective, chitinous and proteinaceous layer, which must be periodically shed through the process of molting, also known as ecdysis, for the organism to grow. This structure is responsible for providing support, protection from physical and biological stress, and helps prevent dehydration in arthropods.