Assertion: mastodon's tusk | /r/HasProperty | modified second incisors
Facets:
value: in the upper jaw
type: LOCATION
Source sentences:
text: Gomphotheres also possessed tusks (which were modified second incisors extending downward from the upper jaw), and most species also had a second set of two tusks that extended upward from the lower jaw.
text: The tusks of an elephant are modified second incisors in the upper jaw.