Explanation:

• Anti–CCP antibody → Correct because it has high specificity for rheumatoid arthritis.

• Antinuclear antibody → Incorrect because it is non-specific.

• Rheumatoid factor → Incorrect because it lacks specificity.

• Anti-dsDNA antibody → Incorrect because it is seen in SLE.

• Anti-centromere antibody → Incorrect because it is seen in limited scleroderma.

Explanation:

• Stop the drug immediately → Correct because patient safety is the priority.

• Continue the drug → Incorrect because it may worsen the reaction.

• Reduce the dose only → Incorrect because serious reactions require cessation.

• Add another drug → Incorrect because it may increase interactions.

• Ignore the reaction → Incorrect because it endangers the patient.

Explanation:

• Fetal hemoglobin → Correct because it binds oxygen more strongly than adult hemoglobin.

• Deoxyhemoglobin → Incorrect because it lacks bound oxygen.

• Oxyhemoglobin → Incorrect because it has normal affinity.

• Carbaminohemoglobin → Incorrect because it carries carbon dioxide.

• Methemoglobin → Incorrect because it cannot bind oxygen effectively.

Mitochondria are the powerhouse of the cell, generating ATP via respiration.

Explanation:

• Peripheral vision loss → Correct because glaucoma initially affects peripheral fields.

• Central scotoma → Incorrect because central vision is affected late.

• Temporal hemianopia → Incorrect because it is due to optic tract lesions.

• Altitudinal defect → Incorrect because it occurs later.

• Bitemporal hemianopia → Incorrect because it occurs in optic chiasm lesions.

Explanation:

• Serum ferritin → Correct because it reflects body iron stores accurately.

• Serum iron → Incorrect because it fluctuates daily.

• Total iron-binding capacity → Incorrect because it reflects transferrin levels.

• Hemoglobin level → Incorrect because it reflects anemia, not stores.

• Peripheral blood smear → Incorrect because it shows morphology only.

Explanation:

• Hematemesis → Correct because vomiting of blood indicates upper GI bleeding.

• Melena → Incorrect because it can occur in both upper and lower GI bleeding.

• Hematochezia → Incorrect because it suggests lower GI bleeding.

• Steatorrhea → Incorrect because it indicates fat malabsorption.

• Tenesmus → Incorrect because it is a rectal symptom.

The cell is the basic structural and functional unit of life.

Explanation:

• WHO → Correct because it is the global authority on public health.

• UNICEF → Incorrect because it focuses on child welfare.

• World Bank → Incorrect because it provides financial assistance.

• UNESCO → Incorrect because it focuses on education and culture.

• FAO → Incorrect because it focuses on food and agriculture.

Explanation:

• Echocardiography → Correct because it assesses cardiac structure and function.

• Chest X-ray → Incorrect because it provides limited functional information.

• Electrocardiogram → Incorrect because it assesses rhythm only.

• Pulmonary function test → Incorrect because it is mainly for thoracic surgery.

• Cardiac enzymes → Incorrect because they assess myocardial injury.