Question

summarize this The esophagus is protected from these acids by the esophageal sphincter. This is a muscular valve that keeps fluids in your stomach. But smoking weakens the sphincter. Smoking also allows stomach acid to flow backward into the esophagus.

Answer 1

The esophageal sphincter protects the esophagus from stomach acid but smoking weakens it, allowing acid to flow back into the esophagus.