Thoracic vertebrae do not have

Correct Answer: A

Rationale: Thoracic vertebrae (T1-T12) lack transverse foramina, present in cervical vertebrae for arteries. 'Transverse foramina,' is correct, per anatomy texts (e.g., Moore's Clinically Oriented Anatomy). 'Transverse processes,' articulate ribs. 'Pedicle,' and 'Spinous processes,' are standard features. The absence of transverse foramina in thoracic vertebrae makes A the accurate answer.

Correct Answer: C

Rationale: Parathyroid hormone (PTH) increases plasma calcium by mobilizing bone calcium and renal reabsorption when levels drop. 'Parathyroid hormone,' is correct, per endocrinology texts like Williams, countering hypocalcemia. 'Calcitonin,' lowers calcium, opposing PTH. 'Aldosterone,' regulates sodium, not calcium directly. 'Adrenaline,' affects metabolism, not calcium. PTH's specific response to low calcium, restoring balance, makes C the precise answer, rooted in calcium homeostasis.

Correct Answer: B

Rationale: Oogenesis is the formation of ova (eggs) in the ovaries, from oogonia to mature oocytes. 'Oogenesis,' is correct, per reproductive physiology (e.g., Tortora). 'Spermatogenesis,' is sperm formation. 'Ovulation,' is egg release. 'Fertilization,' is conception. Oogenesis' full developmental process makes B the accurate answer, specific to female gametes.

Correct Answer: B

Rationale: The loop of Henle extends into the renal medulla, creating a concentration gradient for urine. 'Loop of Henle,' is correct, per anatomy texts like Moore, with its descending and ascending limbs medullary. 'Proximal convoluted tubule,' and 'Distal convoluted tubule,' are cortical. 'Bowman's capsule,' is in the cortex. The loop's medullary location distinguishes B as the accurate answer.

Correct Answer: D

Rationale: Respiration rate adjusts to metabolic demands and gas levels. 'Body weight,' is correct as the exception, not directly affecting rate, per physiology (e.g., West). 'Carbon dioxide,' drives ventilation via pH. 'Oxygen,' influences in hypoxia. 'Temperature,' alters metabolism. Weight's indirect impact (e.g., obesity on mechanics) contrasts with direct triggers, making D the precise answer.