The thinnest epidermis is situated on

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: 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.

Correct Answer: D

Rationale: The correct answer is D: Stratum germinativum. This layer is also known as the stratum basale and is the innermost layer of the epidermis where cell division and renewal occur. It contains stem cells that continuously divide to produce new keratinocytes. The other choices, A: Stratum granulosum, B: Stratum lucidum, and C: Stratum spinosum are all layers of the epidermis, but they are not the innermost layer where cell division primarily takes place.

Correct Answer: A

Rationale: The correct answer is A: Hyponychium. The hyponychium is the layer of stratum corneum located just under the free-edge of the nail. It serves as a protective barrier to prevent microorganisms from entering the nail bed. The lunula (B) is the white, crescent-shaped area at the base of the nail. The eponychium (C) is the cuticle that covers the base of the nail. The nail root (D) is the part of the nail embedded in the skin. Therefore, the hyponychium is the most appropriate answer as it specifically refers to the stratum corneum under the free-edge of the nail.