Choose the correct answer to fill in each of the blanks in the passage.
Ecotourism is booming and many tour operators say this is helpful to nature. Every year, millions of people visit protected natural areas to observe rare species. (12) __________, a new report casts doubt on this form of tourism. The report, (13) __________ in the journal 'Trends in Ecology and Evolution,' suggests that ecotourism damages more than helps nature. Researchers believe tourists disrupt animals in their natural (14) __________. They pointed to a recent event in Costa Rica where turtles had problems (15) __________ their eggs because of the many tourists who had gathered on the beach to watch them.
The report says that ecotourism is making animals bolder. A human presence makes animals tamer and less cautious about other animals. This could (16) __________ them at risk of being attacked by their natural predators, so more of them will be killed. The report said that when animals interact (17) __________ humans, "they may let down their guard".
