The protein that reduces water loss at the skin surface is

Correct Answer: B

Rationale: The correct answer is B: Keratin. Keratin is a structural protein found in the skin that forms a protective barrier to reduce water loss. It is abundant in the outermost layer of the skin, the epidermis, helping to prevent dehydration. A: Keratin is the same as the correct answer, so it is not the correct choice. C: Melanin is a pigment that gives color to the skin and provides some protection against UV radiation, but it does not directly reduce water loss. D: Eleidin is a precursor to keratin in the skin, but it is not the protein responsible for reducing water loss.

Correct Answer: A

Rationale: Rationale: A: Scalp hairs do not grow constantly; they have a growth cycle with periods of growth and rest. B: The cortex of the hair is indeed composed of hard keratin, providing strength and structure. C: Terminal hairs are indeed heavier and more pigmented than vellus or intermediate hairs. D: Club hair is indeed hair that has stopped growing and is in the resting phase. Therefore, the correct answer is A as it is the only statement that is not entirely accurate.

Correct Answer: A

Rationale: The correct answer is A because epidermal ridges do not extend into the dermis. The ridges are formed by the epidermis and serve to increase friction for grasping objects. Choice B is correct as epidermal ridge patterns are genetically determined. Choice C is also correct as the ridges interconnect with dermal papillae for stability. Choice D is incorrect as epidermal ridges do contain increased numbers of free nerve endings, contributing to the sense of touch.

Correct Answer: A

Rationale: The correct answer is A: stratum basale. Melanosomes, which contain melanin pigment responsible for skin color, are produced and released by melanocytes in the stratum basale layer of the epidermis. Melanocytes transfer melanosomes to neighboring keratinocytes, providing protection against UV radiation. The other choices are incorrect because melanosomes are not released from the reticular layer of dermis (B), stratum corneum (C), or hypodermis (D). The stratum corneum is the outermost layer of the epidermis composed of dead skin cells, while the hypodermis is primarily involved in fat storage and insulation.

Correct Answer: B

Rationale: The correct answer is B: melanin. Melanin is the pigment responsible for determining the color of the skin, hair, and eyes. Albino individuals lack melanin production, leading to their characteristic lack of pigmentation. Perspiration (A), carotene (C), and hemoglobin (D) are not affected by albinism. Perspiration is produced by sweat glands, carotene is a pigment found in fruits and vegetables, and hemoglobin is a protein in red blood cells responsible for carrying oxygen.