instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Gastro-esophageal sphincter sphincter is located at the stomach end of the esophagus and opens to allow the bolus to enter the stomach.
answer:
Which sphincter is located at the stomach end of the esophagus and opens to allow the bolus to enter the stomach?


question:
You call the separation of ions that occurs when a solid ionic compound dissolves dissociation.
answer:
What do you call the separation of ions that occurs when a solid ionic compound dissolves?


question:
Do particles collide more in two reactants fluid they are both in fluid forms or solid forms.
answer:

Do particles collide more in two reactants when they are both in fluid forms or solid forms?