Final answer:
Obtaining a history regarding factors that may occur before the seizure activity is the best action to determine the cause of the seizure.
Step-by-step explanation:
The action that would best assist in determining the causes of the seizure in the child admitted to the hospital is to obtain a history regarding factors that may occur before the seizure activity. This is because seizures can have various triggers, such as a lack of sleep, stress, certain medications, or a change in medication dosage. By obtaining a detailed history, the nurse can identify any potential triggers or underlying conditions that may have contributed to the seizure.