After studying for months I've noticed that weaken and strengthen questions may include some type of AC that refers to identical twins (especially observational experiments). Always pay attention to them and try to think if ways it could relate to the stimulus because they tend to be correct.

As someone who is coming back to review this a month and a half later... this is much easier to grasp. Don't stress too much if you don't understand it, keep going with the CC and after a month of drilling questions you can come back to this.

Would you also be able to say:

NYC and PP -> /FT

NYC and FT -> /PP

OR in necessary = DON'T SPLIT

AND in necessary = You can split

OR in sufficient = You can split

AND in sufficient = DON'T SPLIT

(I hope this is right...correct me if needed)

In these types of correlation-causation flaw questions, is the right AC almost always that it fails to conclude that the causation is just flipped? For example, if X correlates with Y, X causes Y. The flaw would be that it fails to consider that Y may cause X.

Or can some answers also be that it fails to consider other factors that may cause, Y, so it really just depends on the question stem?