3902
We found significant variation among consumers within and among sites in carbon source ; this may be related to within - site differences in diet and foraging habitat , and to among - site differences in environmental conditions that influence primary production .
 Chemical: carbon
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: carbon 
Answer:
 Chemical: carbon