Arrector pili muscles are-

Correct Answer: C

Rationale: The correct answer is C: Involuntary. Arrector pili muscles are small muscles attached to hair follicles that contract involuntarily in response to various stimuli like cold or fear. They cause hairs to stand on end, known as "goosebumps." Choice A is incorrect because arrector pili muscles are not under voluntary control. Choice B is incorrect because they are purely involuntary. Choice D is incorrect as the correct answer is C.

Correct Answer: C

Rationale: The correct answer is C: Nerves. Nails do not contain nerves, which are responsible for transmitting pain signals to the brain. Without nerves, the sensation of pain cannot be felt when cutting the nails. Blood vessels (choice A) and bones (choice B) are not directly related to the sensation of pain in this scenario. Choice D is incorrect as nails do not contain any of these structures that would transmit pain. In summary, the absence of nerves in nails is the reason why we do not feel pain when cutting them.

Correct Answer: A

Rationale: The correct answer is A: Dermis. Corium is another name for the dermis, the layer of skin beneath the epidermis. The dermis contains blood vessels, nerves, hair follicles, and sweat glands. The epidermis is the outermost layer of skin and is primarily composed of dead skin cells. Choice B (Epidermis) is incorrect because corium does not refer to the epidermis. Choice C (Both (1) and (2)) is incorrect because corium specifically refers to the dermis only. Choice D (None) is incorrect as corium is indeed another term for the dermis.

Correct Answer: A

Rationale: The correct answer is A: Oily. Sebaceous glands secrete an oily substance called sebum, which helps lubricate and waterproof the skin and hair. Sebum is composed of lipids and fatty acids, giving it an oily consistency. Choice B (Watery) is incorrect as sebaceous glands do not secrete a watery substance. Choice C (Creamy) is incorrect as sebum is not creamy in texture. Choice D (Mucoid) is incorrect as sebaceous glands do not secrete a mucoid substance. The oily nature of sebum is essential for maintaining skin health and function.

Correct Answer: A

Rationale: The correct answer is A: Stratum germinativum. This layer of stem cells constantly divides to renew the epidermis. The stratum germinativum is also known as the basal layer and is located at the bottom of the epidermis. It contains actively dividing cells responsible for producing new skin cells. The basal lamina (B) is a structure that separates the epidermis from the dermis but does not contain dividing stem cells. The stratum corneum (C) is the outermost layer of the epidermis composed of dead skin cells. The stratum granulosum (D) is a layer of the epidermis where cells begin to flatten and lose their nuclei, but it is not where active cell division occurs.