Answer: D. Atrophy

Explanation: Osteoporosis is bone mass loss (atrophy), not hypertrophy, hyperplasia, or metaplasia.

Answer: B. Iris

Explanation: The iris is the visible colored ring of the eye, controlling light entry through pupil dilation and constriction.

Answer: D. Tunica albuginea

Explanation: The tunica albuginea is the tough, fibrous covering of the testes that provides structural support.

Answer: C. Connective tissues

Explanation: Sarcomas are malignant tumors originating from connective tissues such as bone, cartilage, and muscle.

Answer: B. S phase

Explanation: During the S phase of the cell cycle, DNA replication occurs, creating two identical sister chromatids.

Answer: A. Juxtaglomerular cells (JGCs) of kidney

Explanation: Renin is secreted by juxtaglomerular cells in the renal afferent arterioles to regulate blood pressure.

Answer: C. Kaposi sarcoma

Explanation: Kaposi sarcoma is the most common neoplasm in AIDS patients, caused by human herpesvirus 8.

Answer: C. Accessory

Explanation: The accessory nerve (CN XI) provides motor innervation to sternocleidomastoid and trapezius muscles.

Answer: D. Starch

Explanation: Salivary α-amylase hydrolyzes starch into maltose and dextrins, initiating carbohydrate digestion in the mouth.

Answer: B. Tidal volume

Explanation: Tidal volume is the volume of air inhaled or exhaled in a normal breath, typically ~500 mL in adults.

Answer: C. X

Explanation: The vagus nerve (CN X) provides parasympathetic innervation to the heart, slowing heart rate.

Answer: D. Fibrous joints of the skull

Explanation: Cranial sutures are immovable fibrous joints between skull bones.

Answer: A. Mastication; deglutition

Explanation: Chewing is mastication; swallowing is deglutition.

Answer: A. Addison's disease

Explanation: Addison’s is adrenal insufficiency; Conn’s, Cushing’s syndromes/disease are hyperactivity disorders.

Answer: B. Increased HDL

Explanation: Insulin resistance typically causes increased LDL, triglycerides, reduced HDL; increased HDL is not associated.

Answer: D. Creatinine Clearance

Explanation: Creatinine clearance approximates GFR more closely than insulin, BUN, or albumin clearance.

Answer: A. GLUT 4

Explanation: Insulin promotes translocation of GLUT4 to the cell membrane in muscle/adipose.

Answer: C. Thyrotoxicosis

Explanation: Autoimmune IgG in Graves’ disease stimulates TSH receptors, causing thyrotoxicosis.

Answer: C. Clotting Factor VIII

Explanation: Hemophilia A arises from deficiency of factor VIII in the intrinsic coagulation pathway.

Answer: A. Antigens

Explanation: Blood groups are defined by antigens on RBC surfaces; MHC present on WBCs, not RBC-mediated grouping.