Assertion: circulatory system's heart | /r/HasProperty | hollow organ
Facets:
Source sentences:
text: The heart is a hollow organ with four flexible and resilient inner cham­bers.
text: His new system completely altered the Galenic concept of blood circulation, proving that the heart is a hollow muscle that contracts regularly to provide the single motive force of the blood's movement.
text: The heart is a hollow muscular organ shaped like a blunt cone and located in the chest behind the sternum (breast bone).