Sex libido is provoked by

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: C

Rationale: The correct answer is C: Conjunctiva. The conjunctiva is a thin, transparent mucous membrane that covers the front surface of the eye and lines the inside of the eyelids. It is the thinnest epidermis as it is only one cell thick, allowing for transparency and protection of the eye. The face, nipples, and lips have thicker epidermis layers compared to the conjunctiva, making them incorrect choices. Thus, the conjunctiva is the correct answer due to its unique thin structure and location.

Correct Answer: D

Rationale: Keratin found in rabbit skin is classified as a scleroprotein, which is a type of structural protein. Keratin is known for its tough and fibrous nature, providing strength and protection to the skin. Scleroproteins are characterized by their high tensile strength and are commonly found in structural tissues like skin, hair, and nails. Lipoproteins consist of lipids and proteins, glycoproteins have carbohydrate groups attached to the protein, and mucoproteins contain mucopolysaccharides. These types of proteins do not accurately describe the composition and function of keratin in rabbit skin.

Correct Answer: A

Rationale: Rationale: 1. Metachrosis refers to the ability of amphibians to change the intensity of their skin color. 2. Amphibians use metachrosis for camouflage, communication, and temperature regulation. 3. This process is not about shedding skin (B), thermoregulation (C), or metamorphosis (D). Summary of Incorrect Choices: B: Incorrect as metachrosis is about changing skin color, not shedding stratum corneum. C: Incorrect as metachrosis is not directly related to thermoregulation. D: Incorrect as metachrosis does not involve the transformation from larva to adult, which is metamorphosis.

Correct Answer: D

Rationale: Step 1: When a bird is transferred to a colder environment (10ºC), its body temperature tends to drop. Step 2: To maintain its body temperature, the bird needs to conserve and produce more heat internally. Step 3: This increased conservation and production of heat help the bird to keep its body temperature at the original constant level. Step 4: Therefore, option D is correct as it accurately describes the physiological response of a bird to a decrease in environmental temperature. Summary: Option A is incorrect because dissipation of heat does not maintain the body temperature but rather leads to a decline. Option B is incorrect as it suggests a decline without considering the bird's ability to regulate its temperature. Option C is incorrect as increased production and conservation of heat would not result in a rise above normal body temperature in response to a colder environment.