Although the first humans came to Australia 56,000 years ago and undoubtedly brought new diseases with them, human-bo...

shunhe on August 14, 2020

Hi @mb159701,

Thanks for the question! So first, we have to figure out what the flaw in the stimulus is, and to do that, we have to understand the stimulus. So let’s walk through the stimulus first. We’re told that even though the first humans in Australia probably brought new diseases with them, those diseases probably weren’t the reason for the large extinction of a bunch of animals/birds that happened afterwards. This is the conclusion of the argument. Why does the author think this? Well, because more than 55 different species disappeared at about the same time, and no one disease could’ve done that by itself.

So now we can stop and think about what the flaw is before looking at the answer choices. And here, it seems like the argument is saying, “Because one disease can’t do it, all the diseases together couldn’t have done it.” But that’s a pretty bad argument, right? We know that there were multiple diseases. So maybe one disease got rid of 5 species, another disease got rid of another 10, and etc. And so that’s the flaw that we should look to be paralleled.

Now take a look at (B), which tells us that I can fix some things and you can fix some things, but us two put together can’t fix the whole apartment. Why? Because there’s a broken window and a door, and neither of us alone can fix both a broken door and a broken window. But again, that’s attributing what’s true of a part to the whole (the two of us). What if I can fix doors, and you can fix windows? Then we can cover the apartment by ourselves. So (B) matches the flaw in the argument, and is the correct answer.

Hope this helps! Feel free to ask any other questions that you might have.