6252
Trout were exposed to either control ( without TiO ( 2 ) ) , 1 mg l ( - 1 ) TiO ( 2 ) NPs or 1 mg l ( - 1 ) bulk TiO ( 2 ) for 14 days .
 TiO ( 2 ), TiO ( 2 ), TiO ( 2 )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 TiO ( 2 ), TiO ( 2 ), TiO ( 2 )