897
Bis - loop derivative 6 forms no homodimers for steric reasons , but a stoichiometric mixture with the open - chain tetraalkenyl derivative 7a contains exclusively the heterodimer .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Anatomy 
Text: {0} 
Answer:
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