Question

In cockroach sclerites are joined by
(a) Terga
(b) Sterna
(c) Pleura
(d) Arthrodial membrane

Answer 1

Hint: A thin flexible membrane known as the Articular Membrane is fused in cockroach sclerites. The articular membrane is an arthropod specialty. It is a flexible membrane that is, in essence, non-sclerotic and present between the sclerites of the arthropod segmented body.

Complete answer:
The cockroach's whole body is enclosed by a chitinous, rigid exoskeleton. The exoskeleton has hardened plates in each segment, called sclerites, which are joined by a thin and flexible articular membrane known as the arthrodial membrane.

So, the correct answer is, ‘Arthrodial membrane’.

Additional Information:
Sclerite, a hard exoskeleton, brown, is made up of chitin.
In Arthropoda, the hardening that creates sclerites is achieved either by cross-linking protein chains in the exocuticle, a process called sclerotization, or by adding minerals such as calcium carbonate into the exoskeleton regions, or both. The exoskeleton of an arthropod is divided into various sclerites, joined by regions or sutures that are less sclerotic and membranous.
A body section of dorsal sclerites, sometimes platelike, is known as tergites. Equally, a body segment's ventral sclerites are referred to as sternites. Separate sclerites are called pleurites for the lateral parts of body segments, the pleura.

Note: The body is covered/supported by a chitinous exoskeleton in a cockroach, it is secreted by the hypodermis' underlying cells. This exoskeleton is divided into smaller parts called sclerites, connected by a soft and flexible layer called the arthrodial membrane that lacks exocuticle so that the body can move flexibly.