Set 4: Command of Evidence (Advanced)

Explanation

Answer: C

PASSAGE

Herd immunity occurs when enough of a population is immune to stop disease spread. The threshold varies: measles requires ~95% immunity, while polio needs ~80%. Vaccine hesitancy threatens this protection.

Why does the herd immunity threshold vary?

A. All diseases spread the same way.

B. More contagious diseases require higher immunity levels.

C. Thresholds are arbitrary.✓ Correct

D. Vaccine efficacy is identical.

Detailed Explanation

This question requires you to identify evidence that supports a claim. Measles (more contagious) needs 95%; polio 80% = contagiousness affects threshold. The best evidence directly and explicitly supports the stated claim without requiring assumptions. Match specific textual details or data points to the claim being made. The correct answer provides clear, direct support. Strong evidence directly addresses the claim without requiring additional interpretation. When evaluating options, look for quotes or data that explicitly support the statement. Weak evidence may be tangentially related but doesn't provide direct proof.

Key Evidence:

• "Herd immunity occurs when enough of a population is immune to stop disease spread"

• "The threshold varies: measles requires ~95% immunity, while polio needs ~80%"

Why others are wrong: A (This option is incorrect.), B (This option is incorrect.), D (This option is incorrect.).