A、Frog and eagle. B、Snake and pigeon. C、Elephant and lion. D、Wolf and tiger. A

W: Hi, Bill, how is it going?
M: Oh, hi, Jane. I’m OK. How about you?
W: You can probably tell just by looking at me. I’ve been really busy. Hey,(12)what are you reading?
M:(12)A pretty interesting article. My biology professor assigned it, and I thought I just look it over. But I got really involved in it. It’s about endangered species.
W: That sounds pretty interesting.(13)I’m getting frustrated with the two research papers I’m struggling with. And can you believe they are both due on the same day?
M: That’s tough.
W: I’ll get through it. So what’s this you are reading?
M: Well, it’s basically about the choices environment advocates faced with. You know, on these days when funding is so hard to come by.
W: Wait a minute. Is the focus on biology or economics?
M: Both. Environment advocates don’t have enough funding to save every endangered species in the world, so they have to decide based on what would be lost if a species became extinct.
W: Can you give me an example of what you mean?
M:(14)For instance, two animals, the spotted eagle and the tailed frog. The article says the frog is unique. It has no relatives.
W: So, if that frog became extinct, we’d lose an important link in the chain of revolution, right?
M: Exactly. But that isn’t so for the eagle.(15)So for environment advocates, it might be a clear choice of which animal to save.
W: I see. I am glad I don’t have to make that kind of decision.