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A challenge for ecotoxicologists is to predict how joint effects of climatic stress and toxicants measured at the individual level ( e . g . , reduced survival and reproduction ) will be manifested at the population level ( e . g . , population growth rate , extinction risk ) and community level ( e . g . , species richness , food - web structure ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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