2970
The thickness and density of as - grown flower clusters can be readily tuned by tailoring growth parameters , such as growth time , the addition of cations of different valence and size , initial concentrations of precursor and cation , growth temperature , and acidity .
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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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