In rabbit, hairs and most of the glands are developed from

Correct Answer: A

Rationale: The correct answer is A: Epidermis. In rabbits, hairs and most glands are developed from the epidermis, the outermost layer of the skin. The epidermis contains specialized cells that differentiate into hair follicles and various glands. The dermis (choice B) is the layer beneath the epidermis, primarily consisting of connective tissue. The subcutaneous layer (choice C) is primarily made of fat cells and helps insulate the body. The reticular layer (choice D) is part of the dermis and provides structural support. Therefore, the epidermis is the correct choice as it is the primary source of hair and gland development in rabbits.

Correct Answer: C

Rationale: The correct answer is C: Apocrine. Mammary glands secrete milk through the process of apocrine secretion, where the cell membrane buds off to release the secretory product. This is different from merocrine secretion (choice A) where the secretory product is released by exocytosis without any loss of cytoplasm, and holocrine secretion (choice B) where entire cells are released with their secretory product. Choice D is incorrect because mammary glands do indeed secrete milk through apocrine secretion.

Correct Answer: B

Rationale: The correct answer is B: Dermis. Leather is obtained from the dermis layer of animal skin, where the collagen fibers are tightly packed, providing strength and durability. The dermis contains the necessary components for tanning and processing into leather. Epidermis (A) is the outermost layer of the skin and does not contain the required collagen fibers. Adipose tissues (C) are responsible for fat storage and do not contribute to leather production. Collagen fibers (D) are present in the dermis, but the process of converting them into leather involves the entire dermal layer, not just the fibers alone.

Correct Answer: C

Rationale: The correct answer is C: Involuntary. Arrector pili muscles are small muscles attached to hair follicles that contract involuntarily in response to various stimuli like cold or fear. They cause hairs to stand on end, known as "goosebumps." Choice A is incorrect because arrector pili muscles are not under voluntary control. Choice B is incorrect because they are purely involuntary. Choice D is incorrect as the correct answer is C.

Correct Answer: C

Rationale: The correct answer is C: Less sweat in cold weather. During cold weather, the body's sweat glands produce less sweat as a way to conserve heat. This decrease in sweat production leads to less moisture on the skin, causing it to become dry. Vasodilation (choice A) is the widening of blood vessels, which can actually lead to increased moisture on the skin. Vasoconstriction (choice B) is the narrowing of blood vessels, which can affect blood flow but not directly contribute to dry skin. Choice D is incorrect as less sweat production in cold weather is the primary reason for dry skin.