Which of the skin layer is not pierced by arterioles-

Correct Answer: C

Rationale: The correct answer is C: Epidermis. Arterioles are small blood vessels that supply oxygen and nutrients to tissues. The epidermis is the outermost layer of the skin and does not contain blood vessels. Therefore, arterioles do not pierce through the epidermis. The dermis (choice A) and subcutaneous layer (choice B) both contain blood vessels, so arterioles do pierce through them. Muscles (choice D) are not part of the skin layers, so arterioles do not pierce through muscles either. In summary, the epidermis is the only skin layer that is not pierced by arterioles because it lacks blood vessels.

Correct Answer: A

Rationale: The correct answer is A because the skin of a rabbit is typically dry, thin, soft, and hairy. Rabbits have delicate skin with a thin layer of fur, making it soft to the touch. The hair on the skin provides insulation and protection. Choice B is incorrect because rabbit skin is not typically hairless. Choices C and D are incorrect as rabbit skin is not thick or hard; it is known for its thin and delicate nature.

Correct Answer: B

Rationale: The correct answer is B: Sebaceous gland. This gland produces sebum, an oily substance that lubricates the skin and hair. It opens into the hair follicle to distribute sebum along the hair shaft. Sweat glands (choice A) release sweat onto the skin surface, not into hair follicles. Perineal glands (choice C) are located in the genital area and do not open into hair follicles. Zeis glands (choice D) are associated with eyelash follicles, not hair follicles in general. Therefore, the sebaceous gland is the only gland among the choices that opens into hair follicles.

Correct Answer: A

Rationale: The correct answer is A: Perineal glands. The perineal glands, also known as apocrine glands, are responsible for producing pheromones that can stimulate sex libido in humans. These glands are located in the genital area and produce a specific scent that can attract potential mates. Sebaceous glands (choice B) are responsible for producing oil to lubricate the skin and hair, but not directly related to sex libido. Sweat glands (choice C) regulate body temperature by producing sweat, but do not play a direct role in provoking sex libido. Choice D is incorrect because not all of the above glands mentioned are related to sex libido; only the perineal glands are directly linked to stimulating sex drive.

Correct Answer: A

Rationale: The correct answer is A: Skin. Vitamin D is synthesized in the skin when it is exposed to sunlight. UV rays convert a form of cholesterol in the skin into Vitamin D. The liver and kidney play roles in converting and activating Vitamin D, but they are not where Vitamin D is initially synthesized. The stomach is not involved in the synthesis of Vitamin D. So, the skin is the correct choice for the synthesis of Vitamin D in the presence of sunlight.