某生物兴趣小组为了研究“光对豌豆发芽的影响”，在两个花盆里种了豌豆，并设计如下实验：(    )

根据短文理解，从A、B、C三个选项中选择最佳答案填空。

    Ebola (埃博拉) is a river in Africa. In 1976, a 1 virus (病毒) was found there. The virus can cause people to get very sick and even 2. So people call the virus Ebola.

    Last year Ebola caused the worst problem in western Africa, and 3 spread very quickly. Medical experts all over the world did their best to stop Ebola and to treat the people who were sick.

    Ebola 4 starts with fever and headache, kind of like the flu. But it can get worse and cause serious bleeding and 5 problems. It's very important tor infected (受感染的) people to get treatment right away. People who have Ebola need to be cared for in a special way 6 the illness doesn't spread to doctors, nurses or others in their families.        

    Doctors aren't sure how the 7 person got Ebola, but they think people picked up the virus from infected animals. People can get the virus by touching an infected person's drops of 8. But Ebola doesn't spread through food or water like some viruses 9. It also doesn't travel through the air like cold or flu viruses do. In areas where the Ebola virus is, anyone who doesn't feel 10 should get medical held immediately.

狼

    一屠晚归，担中肉尽，止有剩骨。途中两狼，缀行甚远。屠惧，投以骨。一狼得骨止，一狼仍从。复投之，后狼止而前狼又至。骨已尽矣。而两狼之并驱如故。屠大窘，恐前后受其敌。顾野有麦场，场主积薪其中，苫蔽成丘。屠乃奔倚其下，弛担持刀。狼不敢前，眈眈相向。少时，一狼径去，其一犬坐于前。久之，目似瞑，意暇甚。屠暴起，以刀劈狼首，又数刀毙之。方欲行，转视积薪后，一狼洞其中，意将隧入以攻其后也。身已半入，止露尻尾。屠自后断其股，亦毙之。乃悟前狼假寐，盖以诱敌。

    狼亦黠矣，而顷刻两毙，禽兽之变诈几何哉？止增笑耳。