33951
Since the Cambrian explosion , five further major mass extinctions have significantly exceeded the background extinction rate .
 location: Cambrian
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Cambrian 
Answer:
 location: Cambrian