Assertion: giraffe's blood vessel | /r/HasProperty | equipped with valve
Facets:
Source sentences:
text: The animal has a specialized cardiovascular system that keeps blood moving adequately to the brain and heart when it moves its neck and head around, ensuring that bending down to take a sip of water won't cause a possibly lethal head rush [source: Dagg and Foster]. Giraffes' blood vessels are equipped with valves that prevent blood from backtracking due to gravity [source: