Assertion: penguin's bone | /r/HasProperty | filled with marrow
Facets:
Source sentences:
text: Penguins have thicker bones that are filled with marrow, which also helps to keep them warm.
text: Scientists, so mystified by the kiwi's strange properties—which include feathers that feel like hair, heavy bones filled with marrow, and nostrils on the tip of their nose (rather than on the base of their beak like most birds)—have sometimes called them "honorary mammals.