Which of the following symptoms specifically indicates severe pesticide exposure?

Severe pesticide exposure can lead to significant health issues, and coma is a critical symptom that indicates a serious condition. The presence of coma signifies a profound level of toxicity, implying that the central nervous system has been severely impacted. This level of exposure may result from high doses of pesticides or prolonged exposure, affecting brain function to the extent that the individual cannot be awakened or is unresponsive. Recognizing coma as a symptom is crucial, as it requires immediate medical attention and intervention to prevent further health complications.

Other symptoms listed, such as nausea, dizziness, and headache, can be indicative of less severe pesticide exposure and are often considered general symptoms that can arise from various conditions, not just pesticide poisoning. While these symptoms should not be ignored, they do not signal the extreme urgency that coma does, making it clear that coma is the most definitive indicator of severe pesticide exposure among the options provided.