The SAT grammar test has lots of questions involving agreement, fuzzy antecedents, inexact words, and parallelism.
In our quest for low-hanging fruit on the SAT, some of the easier apples to pluck are in that last category (as below), because they are based on such a clear rule -- No. 19 in The Elements of Style: Express coordinate ideas in similar form.
When people gave up the hunter-gatherer way
of life and began to cultivate the soil
and grow their food, they often
became less mobile , built more substantial residences, and
more effective means of storage.