2062
In the present study the role of habituation to the experimental environment on the stimulant effect of nicotine in rats was examined .
 Chemical: nicotine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: nicotine 
Answer:
 Chemical: nicotine