The sentence "The farmer was alone in the undulating field of wheat" is in the passive voice. Here's why:
1. Passive voice typically includes a form of the verb "to be" (in this case, "was") followed by a past participle (in this case, "alone").
2. In passive voice, the subject of the sentence (the farmer) is acted upon by the verb rather than performing the action.
3. In this sentence, the farmer is described as being alone in the field, which indicates a state or condition the farmer is in rather than the farmer actively doing something.
In conclusion, the sentence is in passive voice because it emphasizes the state of being of the farmer rather than the farmer actively engaging in an action.
