单选题 The Northern Pike is a very bad fish. It is a big, hungry fish, and swallows little fish such as trout and perch. Many Northern Pikes live in Lake Davis. They are killing all the smaller fish in the lake. The Northern Pike are a serious threat to the lake because they eat all the smaller fish. Soon, all other species of fish in the lake will be killed off. This is not healthy for the environment.
Experts are afraid that the Northern Pike will swim out of Lake Davis through many smaller rivers that feed into the lake. They could spread all over the country and damage many other water environments. If that happens, it would be too late to stop the Northern Pike.
For ten years, officials have been trying to remove the Northern Pike from Lake Davis. They haw. tried using nets, explosives and poisons. However, the Northern Pike population is still doing well in Lake Davis. Many people do not like the idea of using poison to kill the fish. They worry that the poi- sons are bad for humans who use the water. No trace of the poisons has ever been found in local wells, however.
Scientists are going to try the poison again. This time, they will drain the lake before they add the poison to the water. A public hearing will be held to talk about the problem.

单选题 Why are some people against the use of poisons to kill Northern Pike?

单选题 What will scientists do to make sure the poison works this time?

单选题 What are the experts afraid will happen?

单选题 Why is it a problem if all the smaller fish species die?