Why isn't it A, D or E? I don't understand how deforestation stopped and the koala becomes extinct is consistent with the biologist's claim. In fact, the biologist claims that deforestation at the present rate would mean tue extinction of koalas. If that's the case, wouldn't A be the most appropriate answer?

Jessica,

This is a question that requires you to make the sufficient/necessary distinction.

Here's the deal:
The biologist is saying "Deforestation → Koala Extinct"

The politician is saying "~Deforestation → ~Koala Extinct"

So the politician is making the inverse error when interpreting the biologist's argument.


Now to answer choices (A) and (B):

(A) says "Deforestation & Koala Extinct." Is this consistent with the biologist's argument? Yes. Is it consistent with the politician's? The answer is also yes. The politician acknowledges that you can have "Deforestation & Koala Extinct."

So answer choice (A) is wrong.

Now for (B): "~Deforestation & Koala Extinct"

The biologist's argument allows for this.
Based on his argument, you can have the koala go extinct for reasons other than deforestation.
The politician's argument does NOT allow for this. He says IF you stop deforestation, then you ensure the koala does not go extinct.

We have our disagreement, so (B) is the correct answer choice.


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Oh, and as for answer choice (E), we have no idea what either party thinks about what happens when deforestation is "slowed."