In order to use more precise language, the underlined phrase, "take possession of the new horses" in Sentence (1) should be changed to

We need to be careful to distinguish between the kinds of "units" that we produce in writing, especially formal academic writing, and the kinds of "units" that we produce in conversational speech. Sentences in academic writing are usually syntactically "complete" units with full subjects and predicates. On the other hand, conversational speech proceeds with little bits and pieces of language--few people speak in full sentences. Some grammarians and linguists use the term utterance to refer to the units of spoken conversation. They've invented this term as a way to clarify the unit being studied and as a recognition that while both speech and writing use the same basic grammar they are not completely alike in how they use that grammar.

adopt the horses, just answered it on USA Test Prep. Got it right.