What is known about the influenza virus?
- A It was first found in a group of very old birds.
- B All the different strains can be found in wild birds.
- C It existed over 100 million years ago.
- D It can survive in many different places.
问题
What is known about the influenza viru
参考解析：
[解析] 见本文第一段最后一句。有证据显示病菌通过候鸟从一个地方，一个洲传带到另一个地方，另一个洲。由此可以看出病菌可以在不同的地方存活。
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