4814
At the equator the stable layer of ice might lie under as much as 1 kilometer of material , but at higher latitudes the ice may be just a few centimeters below the surface .
 None
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:  
Answer:
 None