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Answer: BSet 3: Inferences (Intermediate)
Explanation
PASSAGE
Geologists have discovered that the Sahara Desert was once a green savanna, with lakes, rivers, and abundant wildlife. This transformation occurred about 5,000 years ago due to subtle shifts in Earth's orbital patterns that altered monsoon circulation. The change happened gradually enough that human populations adapted by migrating toward the Nile.
What can be inferred about climate change and human adaptation?
A. Climate change always happens too quickly for humans to adapt.
B. Gradual environmental change may allow human populations to migrate and survive.✓ Correct
C. The Sahara has always been a desert.
D. Orbital patterns have no effect on climate.
Detailed Explanation
Change was 'gradual enough' for populations to adapt by migrating—pace allowed survival.
Key Evidence:
• "happened gradually enough"
• "human populations adapted by migrating"
Why others are wrong: A (Gradual change allowed adaptation.), C (It was 'once a green savanna.'), D (Orbital shifts caused the transformation.).