Assertion: oxygen | /r/HasProperty | required
Facets:
value: for all complex life
type: OTHER
value: until the discovery of anaerobic metazoa
type: TEMPORAL
Source sentences:
text: The needs of the body's blood oxygen may fluctuate such as during exercise when more oxygen is required  or when living at higher altitudes.
text: To make ATP from these nutrients, O 2 is required.
text: Until the discovery of anaerobic metazoa, oxygen was thought to be a requirement for all complex life.
text: Higher BOD indicates more oxygen is required, signifying lower water quality.