$A$ : Vomiting is the forcible expulsion of the contents of the upper gastrointestinal tract through the mouth.
$R$ : The strongest stimuli for vomiting are irritation and distension of the stomach.

Excessive stimulation of the vagus nerve in humans may lead to

Anxiety and eating spicy food together in an otherwise normal human,may lead to:

$A$ : In acute constipation,purgatives containing magnesium salts are generally used.
$R$ : The osmotic effect of $Mg^{2+}$ in the intestinal lumen prevents water reabsorption from the intestine. $Mg^{2+}$ increases the solute concentration in the intestinal lumen because $Mg^{2+}$ is absorbed very slowly.

Go through the following statements regarding the disorders of the digestive system. Choose the correct statements and select the appropriate option from the codes given below:
$I.$ Indigestion is caused by the poor supply of digestive enzymes,overeating,anxiety,and a lot of junk food.
$II.$ Constipation,an irregular movement of the bowel,is caused due to poor habits,a fiberless diet,emotional stress,and certain drugs.
$III.$ Indigestion can be caused by milk of magnesia.
$IV.$ Ejection of stomach content is controlled by the hypothalamus of the prosencephalon.

Given below are two statements.
Statement $I$: Defecation is an involuntary process that takes place through the anal opening guarded by sphincter muscles.
Statement $II$: Distension of the rectum stimulates pressure-sensitive receptors that initiate a neural reflex for egestion.
In light of the above statements,select the correct answer from the options given below.