Final answer:
The correct intervention for administering a gastrostomy feeding by gravity is to elevate the head of the bed during and after the feeding to prevent aspiration and other complications.
Step-by-step explanation:
The correct intervention when a nurse is administering a gastrostomy feeding by gravity is to elevate the head of the bed during and after feeding.
This position prevents aspiration, which can occur if the formula flows into the lungs instead of the stomach. In contrast, options such as administering the feeding rapidly, using a small syringe, or doing so while the child is lying flat are not recommended practices and can lead to several complications like aspiration, feeding intolerance, and increased risk of gastroesophageal reflux.