What would be the most likely immediate response to a whole body dose of 2 Gy?

A whole body dose of 2 Gy of radiation is significant enough to induce immediate physiological reactions. At this dosage, which is within the range that can cause acute radiation syndrome (ARS), the body reacts to the cellular damage and stress caused by the ionizing radiation.

Diarrhea, nausea, and vomiting are common symptoms associated with this level of radiation exposure, as they stem from damage to the gastrointestinal (GI) tract lining and the central nervous system's response to radiation stress. The damage to the rapidly dividing cells in the gut can lead to gastrointestinal symptoms as the body's way of expelling toxins and managing the cellular injury.

In contrast, the other responses, like a sense of well-being or increased strength, are not scientifically supported outcomes of radiation exposure. There is no basis for expecting these feelings or reactions at this level of radiation; instead, the body experiences distress and symptoms of illness. Convulsive seizures and edema are also less commonly associated with acute radiation exposure at this dose level. Therefore, the correct response highlights the debilitating effects of radiation and the immediate bodily responses to mitigate the harm caused by such exposure.