Why do stomach contents that leak up to the esophagus cause reflux disease (GERD)?

Why do stomach contents that leak up to the esophagus cause reflux disease (GERD)?

Question 7 options: They are a large bolus which is uncomfortable. Stomach contents are acidic which causes discomfort. Chyme is high in sodium which causes a burning sensation. Saliva is high in enzymes which can cause discomfort.