17665
Anti - bothropic IgY antibodies recognized antigens with molecular masses ranging from 25 kDa to 50 kDa , whereas anti - crotalic IgY antibodies mainly recognized antigens with molecular masses of 14 kDa and 30 kDa .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
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