Passage Summary: A resort tried to kill off mosquitoes by planting trees to attract hungry birds. The birds came and ate the bugs just like they were supposed to, but weirdly, the mosquito problem actually got worse instead of better.

Reasoning: Trees were planted to attract birds that eat mosquitoes; the birds arrived and ate the mosquitoes, but the mosquito population actually increased.

Analysis: We are looking for a 'missing link' that explains how the solution (birds/trees) actually contributed to the problem (mosquitoes). Perhaps the trees provided a perfect new breeding ground for the insects that outweighed the birds' appetite, or maybe the birds themselves drove away a different predator that was even better at killing mosquitoes. The correct answer will provide a reason why the increase in birds or the presence of the trees led to a net gain in the mosquito population despite the birds' snacking habits.