Answer:
Washburn established that stomach contractions happen when he felt hungry.
Explanation:
Washburn conducted an experimental work to establish one factor that pushes or drives hunger. Washburn swallowed a balloon which was attached to a recording device. Then the balloon was inflated to fill the stomach and this resulted in stomach contractions. Then Washburn recorded the feeling of hunger using a key. This way it was established that stomach contractions happen when someone feels hungry. This research was conducted in 1912.
