Assertion: elephant's role | /r/HasProperty | critical
Facets:
Source sentences:
text: African elephants are a keystone species, meaning they play a critical role in their ecosystem.
text: Elephants play a critical role in Botswana’s tourist economy, which drew nearly two million international visitors in 2017.
text: War elephants played a critical role in several key battles in antiquity, but their use declined with the spread of firearms in the early modern period.