Regarding bilirubin:

Correct Answer: D

Rationale: The correct answer is D because in hemolytic anemia, there is an increased breakdown of red blood cells, leading to excess bilirubin production. This results in unconjugated hyperbilirubinemia. Unconjugated bilirubin is less soluble than conjugated bilirubin (Choice A). Conjugated bilirubin is excreted via the bile into the intestine, but not all of it is excreted in this manner (Choice B). Bile duct obstruction typically leads to conjugated hyperbilirubinemia, not unconjugated (Choice C).

Correct Answer: D

Rationale: The correct answer is D because calcium regulation in the blood is primarily controlled by hormones released from the parathyroid and thyroid glands. Parathyroid hormone (PTH) released by the parathyroid glands increases blood calcium levels, while calcitonin released by the thyroid gland decreases blood calcium levels. The other choices are incorrect because the testes primarily produce hormones related to reproduction (not calcium regulation), the adrenal medulla and pancreas are not directly involved in calcium regulation, and the thymus is involved in immune function but not in calcium regulation.

Correct Answer: B

Rationale: The correct answer is B: oxytocin. Oxytocin is the hormone responsible for stimulating the contraction of smooth muscle in the uterus during childbirth and labor. It acts on the smooth muscle cells in the uterine wall, causing them to contract and aiding in the process of childbirth. A: Follicle-stimulating hormone is involved in the regulation of the reproductive system, particularly in the development of ovarian follicles. C: Prolactin is primarily responsible for milk production in the mammary glands. D: Luteinizing hormone triggers ovulation and the formation of the corpus luteum in the ovary. Therefore, the correct answer is B because it directly affects the contraction of smooth muscle in the uterus, which is essential during childbirth.

Correct Answer: A

Rationale: The correct answer is A: Carbohydrates. Amylase is an enzyme that specifically breaks down carbohydrates, such as starch and glycogen, into simpler sugars like glucose. It does this by catalyzing the hydrolysis of alpha-1,4-glycosidic linkages in polysaccharides. Proteins are broken down by protease enzymes, not amylase. Fats are broken down by lipase enzymes. Choice D is incomplete and does not provide a relevant option.

Correct Answer: B

Rationale: The correct answer is B: FALSE. The large intestine does not have villi like the small intestine. Villi are finger-like projections in the small intestine that increase surface area for nutrient absorption. The large intestine primarily absorbs water and electrolytes, and does not have villi. Other choices are incorrect because the large intestine does not have villi and does not aid in absorption like the small intestine.