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Set 3: Command of Evidence

Explanation

Answer: B

PASSAGE

Monarch butterflies migrate thousands of miles from Canada to Mexico each year. Scientists believe they use the position of the sun and Earth's magnetic field to navigate. This remarkable journey takes several generations, with no single butterfly completing the entire round trip.

Which finding, if true, would most directly support the scientists' belief about navigation?

A. Monarchs raised in captivity can still fly long distances.
B. Monarchs with disrupted magnetic sensors become disoriented during migration.✓ Correct
C. Monarchs prefer warmer climates for breeding.
D. The population of monarchs has declined in recent decades.

Detailed Explanation

The claim is that monarchs use 'Earth's magnetic field to navigate. ' If disrupting their magnetic sensors causes disorientation, it directly proves they rely on magnetism for navigation.

Key Evidence:

• "Earth's magnetic field to navigate"

Why others are wrong: A (Flying long distances doesn't prove HOW they navigate.), C (Preference for warmth doesn't explain navigation.), D (Population decline is unrelated to navigation mechanism.).

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