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Set 1: Cross-Text Connections

Explanation

Answer: A

PASSAGE

Text 1 Dark matter is hypothesized to constitute approximately 85% of the universe's matter. Its existence is inferred from gravitational effects on visible matter, such as the rotation speeds of galaxies, which often exceed what visible mass alone can explain. Text 2 Alternative definitions of gravity, such as MOND (Modified Newtonian Dynamics), propose that at low accelerations, gravity behaves differently than Newton or Einstein predicted. These theories attempt to explain galactic rotation curves without invoking unseen mass.

How does Text 2 present an alternative to the scientific consensus described in Text 1?

A. It suggests modifying physical laws rather than assuming the existence of undetectable matter.✓ Correct
B. It proves that dark matter is visible.
C. It argues that galaxies do not rotate.
D. It claims that gravity does not exist.

Detailed Explanation

Text 1: Dark Matter (Unseen mass) explains rotation. Text 2: MOND (Modified laws) explains rotation without mass. Alternative: Modify laws vs Add mass.

Key Evidence:

• "inferred from gravitational effects"

• "gravity behaves differently"

• "without invoking unseen mass"

Why others are wrong: B (Text 1 says inferred.), C (Explains rotation.), D (Modifies it.).

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