19463
In the course of preparing this brief review , we were surprised to see that , except for some earlier eminent morphological studies , little is known about the regulation of the microtubule ( MT ) cytoskeleton and the coordination of MT with the actin - based cytoskeleton to regulate spermatid transport during the epithelia cycle , illustrating that this is a largely neglected area of research in the field .
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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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