3125
Specifically , zebrafish were exposed to control or 0 . 5 micro M PFOS during 1 to 20 , 21 to 120 , or 1 to 120 d postfertilization ( dpf ) .
 Chemical: PFOS
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PFOS