Which layer of skin of hands is highly developed in labourers who work hard with their hands-

Correct Answer: A

Rationale: The correct answer is A: Dermis of palms. The dermis of the palms is highly developed in laborers due to constant friction and pressure from manual labor. This layer thickens to provide protection and support. The subdermal layer is not typically highly developed in response to labor, and the epidermal layer may thicken but is not the primary layer affected. Choice D is incorrect because not all layers of the skin are equally affected by manual labor.

Correct Answer: B

Rationale: The correct answer is B: Perineal glands. Perineal glands are scent glands found in animals to produce pheromones. These glands are responsible for emitting scents used in communication and territorial marking. Zeis glands are sebaceous glands in the eyelids, Ceruminous glands produce earwax, and Sweat glands produce sweat for thermoregulation. Therefore, perineal glands are the only glands specifically known for producing scents.

Correct Answer: A

Rationale: The dermis is mainly composed of fibrous connective tissue, which provides structural support and flexibility to the skin. This tissue contains collagen and elastin fibers, giving the skin its strength and elasticity. Nerve fibers and receptors are present in the dermis for sensation, but they are not the main component. Blood capillaries supply nutrients and oxygen to the skin, but they are not the primary composition of the dermis. Elastin proteins are important for elasticity, but they are a component within the fibrous connective tissue in the dermis. Therefore, choice A is correct as it accurately represents the main composition of the dermis.

Correct Answer: B

Rationale: The correct answer is B: Tanning. Tanning is the process of converting raw animal hides into leather by treating them with chemicals to preserve and strengthen the material. Taxidermy is the preserving of animal bodies, not the formation of leather. Keratinization is the process of converting soft tissues into hard structures like hair and nails, not the formation of leather. So, tanning is the only choice directly related to the formation of leather from the skin.

Correct Answer: A

Rationale: The correct answer is A: End organs of Ruffini. These corpuscles are stimulated by hot temperatures due to their function as thermoreceptors. Ruffini corpuscles respond to sustained pressure and warmth, making them sensitive to hot temperatures. The other choices are incorrect because: B: Crases corpuscles respond to deep pressure. C: Bulb corpuscles, also known as Pacinian corpuscles, respond to deep pressure and vibration. D: Meissner's corpuscles respond to light touch and are located in the dermal papillae of hairless skin.