The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, it

The question is incomplete as it does not have the options which are:

A. the movement of swallowed food into the trachea rather than into the esophagus

B. Too rapid emptying from the stomach into the small intestine

C. too rapid emptying of the small intestine into the large intestine

D. regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"

E. the control of defecation

Option-D

Explanation:

The oesophagus is a tube-like structure made of smooth muscle which connects the throat of the humans to the stomach.

At the lower side of the oesophagus, a sphincter is formed by the circular shaped muscle which when constricted does not allow the backflow of the substances from the stomach to the oesophagus.

If the sphincter in the esophagus fails to close, then the acidic content present in the stomach along with the food will flow back to the oesophagus and since the esophagus wall is not prepared for the acidic nature therefore the acidic content will cause the irritation and inflammation in the esophagus, a condition called heartburn.

Thus, Option-D is correct.

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