Biologist: Forest Disappear --> koala will approach extinction

This problem tests your knowledge of sufficient and necessary conditions. Forest disappearing is one of the things that can make a koala approach extinction. But there can be other things as well, such as fires, poaching, etc.

Politician: /Forest Disappear --> /koala will approach extinction

So now the question stem wants an answer that is consistent with the biologist and inconsistent with the politician. So we need to prove the biologists claim true.

What the politician is doing is denying the sufficient, which invalid argument form #2.

B is the correct answer. /Forest disappear --> koala approach extinction.

It demonstrates that forest disappearing could happen but doesn't need to. And thats how a sufficient condition should work. We just know that if forest do disappear, then koala's will approach extinction. And it goes against the politician because the politician thinks that if forests DOES NOT disappear then Koalas WILL NOT approach extinction. But in this answer choice Koalas DO.

Hope this helped at least a little. Good luck!