The cell of stratum germinativum are columnar and very active to form new cells. As new cells are formed the older ones are pushed upwards and at the same time they become-

Correct Answer: A

Rationale: Step-by-step rationale: 1. The stratum germinativum is the deepest layer of the epidermis where new skin cells are formed. 2. New cells are columnar in shape as they are actively dividing and multiplying. 3. As new cells are formed, older cells are pushed upwards towards the surface. 4. As older cells move upwards, they flatten out due to the pressure and tight packing. 5. Therefore, the correct answer is A: Flat, as older cells become flattened as they move towards the surface. Summary: Choice A is correct because older cells in the stratum germinativum become flat as they are pushed upwards. Choices B, C, and D are incorrect as they do not accurately describe the shape transformation of cells in the epidermis.

Correct Answer: A

Rationale: The correct answer is A: Thermoregulation. Sweat glands help regulate body temperature by producing sweat, which evaporates and cools the body. Osmoregulation (B) is the regulation of water and solute concentrations in the body, not the primary function of sweat glands. Excretion (C) is the elimination of waste products, which is not the primary function of sweat glands. "None of the above" (D) is incorrect as sweat glands do play a significant role in thermoregulation.

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.