A、About human beings. B、About mosquitoes. C、About the earth. D、About insects, D

W: Hi! Did you watch that documentary on TV last night?
M: No, I was in a meeting, and unable to go home early. What was it about?
W: It was about insects.
M: Insects?
W: Yes. Do you know? They are the most successful creatures on the earth.
M: What, more successful than humans?
W: Yeah. Because they were around long before people were, and there are far more insects than there are humans. What’s more, they are reproducing all the time.
M: Well, I suppose that’s true.
W: And they are incredibly adaptable.
M: In what way?
W: Well, take mosquitoes for example. You know, the things that spread the disease. What troubles us is that every time we try to wipe out the mosquitoes with some new insecticide, they change their body chemistry.
M: Haven’t they just brought out a new medicine to fight the disease?
W: Yes, they have. But I bet that within five years they’ll be looking for a new one! The mosquitoes will simply adapt again!
M: I think it keeps the scientists employed!
W: I guess so.