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SamA January 19, 2020
Hello @naty0405,Sufficient and necessary statements aren't always written explicitly in an if/then format. We need to recognize them even when they aren't, and this question is a great one to practice with. There are some terms here that we can learn from.
"Bring about" - sufficient brings about necessary. Lightning brings about thunder.
L - - - - - - - > T
In this case, migration brings about intermingling of ideas.
M - - - - - - > II
Let's look at the second half of that sentence. "...intermingling ideas necessary for rapid advances in civilization." This one specifically tells us what the necessary condition is! Intermingling ideas are necessary for rapid advances.
That is where we get RAC - - - - - - - - > II
Do intermingling ideas guarantee rapid advancement? No, because the necessary condition does not guarantee the sufficient condition. This is why B and E are incorrect.