Assertion: blue whale's head | /r/PartOf | 40% of their body
Facets:
value: to take in water
type: PURPOSE
Source sentences:
text: Balaenids have heads that can make up 40% of their body mass to take in water.
text: These animals have very large heads, which can make up as much as 40% of their body mass, and much of the head is the mouth.