Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

[EX Q]: Rod is the general shape of centrioles.
[EX A]: What is the general shape of centrioles?

[EX Q]: Oxygen gas is given off by plants.
[EX A]: Which gas is given off by plants?

[EX Q]: Gastric emptying is regulated by both the stomach and the duodenum.
[EX A]:
Gastric emptying is regulated by both the stomach and what other digestive structure?