Respuesta :

Heartburn is caused by the reflux of stomach acid into the esophagus. This happens when the lower esophageal sphincter (LES), a ring of muscle between the esophagus and the stomach, becomes weak or relaxes inappropriately. When the LES doesn't close properly, stomach

Explanation:

Heartburn is caused by the reflux of stomach acid into the esophagus. This happens when the lower esophageal sphincter (LES), a ring of muscle between the esophagus and the stomach, becomes weak or relaxes inappropriately. When the LES doesn't close properly, stomach

Explanation: