Assertion: homo sapiens's brain | /r/HasProperty | costly
Facets:
value: incredibly
type: DEGREE
Source sentences:
text: Firstly, larger-headed babies are more difficult to give birth to and large brains are costly in terms of nutrient and oxygen requirements.
text: Still, the human brain is an incredibly expensive organ, taking up only about 2 percent of the body's mass yet using more than a fifth of the body's energy, and until about 2 million years ago none of our ancestors had a brain larger than an ape's when compared to body size.