5
Answer: BSet 5: Inferences (Intermediate)
Explanation
PASSAGE
Rewilding projects aim to restore ecosystems by reintroducing species that were locally extinct. When wolves were brought back to Yellowstone, they reduced elk overpopulation, allowing willows to regrow, which stabilized riverbanks and created habitat for beavers and songbirds. This 'trophic cascade' showed how a single species can reshape an entire ecosystem.
What can be inferred about ecosystems?
A. Each species exists independently of others.
B. Removing or adding key species can trigger cascading effects throughout the system.✓ Correct
C. Wolves had no effect on Yellowstone's ecosystem.
D. Trophic cascades are purely theoretical concepts.
Detailed Explanation
Wolves → fewer elk → willows → riverbanks → beavers/birds = cascading effects from one species.
Key Evidence:
• "trophic cascade"
• "a single species can reshape an entire ecosystem"
Why others are wrong: A (The cascade shows interconnection.), C (The passage describes major effects.), D (Yellowstone is a real example.).