Calcium level in the blood is regulated by hormones released from the .

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: 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.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.