题目内容：

Directions: Read the following passage. Fill in each blank with a proper sentence given in the box. Each sentence can be used only once. Note that there are two more sentences than you need.

Ecotourism can put wild animals at risk

Ecotourism has become increasingly popular in recent years. 1. There travelers visit natural environments to fund conservation efforts or promote local economies.

Now, scientists have analyzed more than 100 research studies on how ecotourism affects wild animals. They find the presence of humans changes the way animals behave, and those changes may put them at risk. Therefore, they concluded that such trips can be harmful to the animals.

When animals interact in seemingly kind ways with humans, they may let down their guard. 2.. If this transfers to their interactions with predators（捕食者）, they are more likely to be injured or killed.

The presence of humans can also discourage natural predators. It creates a kind of safe place for smaller animals that may make them bolder. For example, in Grand Teton National Park, elk and pronghorns in areas with more tourists are less alert and spend more time eating.

3. “If animals become accustomed to tourists and if tourism practices enhance this taming, we might create unintended consequences - affecting the behavior or population of a species and influencing the species’ function in its community,” the researchers write.

Ecotourism has effects similar to those of animal domestication and urbanization. Research has shown that domesticated silver foxes become more obedient and less fearful. Fox squirrels and birds that live in urbanized areas are slower to flee from danger. 4.

Scientists hope the new analysis will encourage more research into the interactions between people and wildlife. It is essential to develop further understanding of how various species in various situations respond to human interaction and under what conditions human exposure may place them at risk.

A.As animals learn to relax in the presence of humans, they may become bolder in other situations.

B.This massive amount of ecotourism can be one of the drivers of rapid environmental change.

C.The phenomena result from evolutionary changes, but also from regular interactions with humans.

D.Do not import or release living animals or plants into the wild that could harm native species.

E.In many cases it involves close interaction with wildlife.

F.Interacting with people can cause great change in the characteristics of various species over time.