I feel like this is a good question to ask yourself that is substitutable. "If I'm a cat do I have to be a mammal?" Yes, being a mammal is necessary for being a cat, therefore mammal is the necessary condition in this relationship. This question is substitutable in that you can just ask yourself "If I'm x do I have to be Y?" If the answer is yes then Y is more than likely the necessary condition. Sorry if this has been mentioned but this helped me be able to understand the point enough to simply explain to other people. Also the question you ask yourself should be phrased in relation to the material in the question. I could say "if I'm in Syracuse then I'm in Indiana....I'm in Syracuse therefore I'm in Indiana" and it could be logical true but factually wrong and asking yourself "If I'm in Syracuse do I have to be in Indiana" would make you second guess but if that's what the stimulus says, I hope not, but you would go along with it. Hopefully what I just said is correct too.

Can I not make the domain "Ms Stoops' Class" and then that would make the arrow multi-directional?

#Help

I understand how you get to the conclusion but why is it silent on what happens if the animal serves a leg purpose?

For example:

/Animal does serve leg pur & Resident -> Prohibited

Can I not contrapositive this to:

/Prohibited -> Animal does serve leg pur or /Resident

Or does this mean that it is still silent on what happens when an animal does serve a leg purpose and we only know what happens when they are /prohibited? Sorry, I'm confused.

Could you also say its not all the cats trained by parisian divas, only the fat ones sing lullabies, so we have no knowledge on tall cats trained by parisian divas. The diagram makes it seem like fat cats are the necessity, and the parisian divas are sufficient, I think those words fit here. But i'm just wondering if you can reverse it as well.

In the star wars example if he were to expand and add this "and due to the Star Wars movie being very popular there will be plenty of opportunities to see it". Would this still make the "Even though the Star Wars movie is popular" a concession or now is it context for the premise being added?