16178
The nomads act as an extra level of selection on top of the intense natural selection pressure of the Sahel environment .
 location: Sahel
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: Sahel 
Answer:
 location: Sahel