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The molar ratio of cadmium to selenium in the quantum dot - exposed worms ( 6 . 2 ) is closer to the ratios seen in positive control worms ( 7 . 2 ) than to the pure quantum dots ( 1 . 8 ) , which implies that quantum dots are taken up predominantly in the degraded form .
 Chemical: cadmium; Chemical: selenium
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: cadmium; Chemical: selenium