Assertion: platypus's bone | /r/CapableOf | increase their density
Facets:
value: to provide ballast
type: PURPOSE
Source sentences:
text: As in many other aquatic and semiaquatic vertebrates, the bones show osteosclerosis, increasing their density to provide ballast.
text: As in many other aquatic and semiaquatic vertebrates, the bones show osteosclerosis, increasing their density to provide ballast.