The brains of identical twins are genetically identical. When only one of a pair of identical twins is a schizophreni...

I think what’s helping me in addition to following the steps (1. Identify which choice strengthens 2. Negate choice) is remembering what the conclusion says and key terms in the conclusion. In this instance, I highlighted “damage to the physical structure causes schizophrenia”. And found the answer choice that, when negated, would break down the conclusion. Thus, answer choice B.