Read the sentenceMost people live in river valleys with arable land rather than on the unfertile sands of the desert.

The sentence contrasts “arable land” with “unfertile sands.” Since “arable” means suitable for growing crops, it is the opposite of “unfertile” in this context. The sentence uses an antonym clue, so the answer is “antonym or synonym.”

AI-written and checked against the verified answer.