The head of the radius articulates with the of the humerus.

Correct Answer: D

Rationale: The radial head articulates with the humerus' capitulum in the elbow. 'Capitulum,' is correct, a rounded lateral structure, per anatomy (e.g., Drake's Gray's Anatomy). 'Trochlea,' articulates with the ulna. 'Glenoid cavity,' is in the shoulder. 'Olecranon,' is the ulna's part. Capitulum's specific radial fit makes D the accurate answer.

Correct Answer: C

Rationale: The pancreas functions as both an exocrine gland (digestive enzymes via ducts) and an endocrine gland (insulin, glucagon into blood). 'Pancreas,' is correct, per anatomy texts like Moore, with acini (exocrine) and islets (endocrine). 'Adrenal gland,' and 'Pituitary gland,' are purely endocrine. 'Thyroid gland,' is endocrine only. The pancreas' dual role in digestion and glucose regulation makes C the precise answer, unique among endocrine glands.

Correct Answer: B

Rationale: Polyunsaturated fatty acids (PUFAs) have multiple double bonds. 'Oleic acid,' is correct as the exception, a monounsaturated fatty acid with one double bond, per biochemistry (e.g., Harper's). 'Linoleic acid,' 'Arachidonic acid,' and 'Linolenic acid,' are PUFAs with multiple bonds, essential in diets. Oleic acid's single unsaturation contrasts with PUFAs' plurality, making B the precise answer.

Correct Answer: B

Rationale: The male urethra averages 20 cm, spanning prostatic, membranous, and spongy parts. '20 cm,' is correct, per anatomy texts like Netter, varying slightly (18-22 cm). '15 cm,' is short. '25 cm,' and '30 cm,' exceed typical length. The 20 cm standard reflects its path from bladder to external meatus, making B the accurate answer.

Correct Answer: B

Rationale: Vital capacity is the maximum air exhaled after full inhalation, about 4.8 L. 'Vital capacity,' is correct, per physiology (e.g., Tortora). 'Tidal volume,' is normal breath. 'Residual volume,' stays in lungs. 'Total lung capacity,' includes residual. Vital capacity's exhalable measure distinguishes B as the precise answer.