Complexion of skin in human beings is a mixed effect of -

Correct Answer: C

Rationale: The correct answer is C: Carotene, Melanin, and Haemoglobin. Carotene contributes to the yellowish tone, Melanin is responsible for the color of the skin, and Haemoglobin gives the skin a pinkish hue. Keratin is a protein in the skin and hair, not directly related to complexion. Albinism is a genetic disorder causing lack of melanin production, not a normal component of skin complexion. Carotene, Keratin, and Haemoglobin (option B) do not cover the pigment responsible for skin color (Melanin).

Correct Answer: D

Rationale: The correct answer is D: Sebum. Sebum is the substance secreted by the sebaceous glands in the skin. Sebum helps to lubricate and waterproof the skin and hair. Cerumin (A) is the substance produced by ceruminous glands in the ear canal. Sweat (B) is produced by sweat glands to regulate body temperature. Mucous (C) is produced by mucous glands to protect and lubricate the mucous membranes. Therefore, the correct answer is D as it specifically refers to the substance secreted by the sebaceous glands.

Correct Answer: C

Rationale: The correct answer is C: Below the tail. Perineal glands are located in the perineal region, which is the area between the anus and the external genitalia. This location is below the tail in animals. Choice A is incorrect because perineal glands are not situated in the rectum. Choice B is incorrect as perineal glands are not near mammary glands. Choice D is incorrect as perineal glands are not located in the subcutaneous fat layer. Therefore, the correct location of perineal glands is below the tail.

Correct Answer: D

Rationale: The correct answer is D because the folder upper part of the dermis is composed of both skin papilla and hair papilla. Skin papilla plays a role in nourishing the epidermis, while hair papilla supports hair growth. Choice A, skin papilla only, is incorrect as it does not account for the hair papilla's presence. Choice B, hair papilla only, is also incorrect as it neglects the role of the skin papilla. Choice C, dermal papilla only, is incorrect as it does not specify the individual components involved in the upper part of the dermis. Thus, the correct answer is D, which accurately reflects the presence of both skin papilla and hair papilla in the folder upper part of the dermis.

Correct Answer: B

Rationale: Step 1: Arrector pili muscles are responsible for hair erection. Step 2: Sympathetic nervous system controls arrector pili muscles. Step 3: Adrenaline is released in response to stress, cold, heat, or anger. Step 4: Adrenaline activates sympathetic nervous system. Step 5: Sympathetic stimulation causes contraction of arrector pili muscles, leading to hair erection. Therefore, the correct answer is B: Adrenaline and sympathetic stimulation. Summary: - A: Adrenaline alone is not sufficient as it needs to activate the sympathetic nervous system. - C: Sympathetic stimulation alone does not explain the role of adrenaline. - D: Calcitiotinin is not involved in the contraction of arrector pili muscles.