19891
Thus , rice root hairs on the epidermal layers are exposed to a different redox status of nitrogen species , organic acids , and metal ions than root hairs growing in drained soil .
 Chemical: nitrogen
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: nitrogen 
Answer:
 Chemical: nitrogen