Assertion: okapi's head | /r/HasProperty | lowered
Facets:
Source sentences:
text: The jugular veins contain several (most commonly seven) valves to prevent blood flowing back into the head from the inferior vena cava and right atrium while the head is lowered.
text: A giraffes circulatory system is also specially modified, because the high pressure needed to pump blood up to its head could cause brain damage when the head is lowered.