I'm not sure what guideline you have heard, Kolndom-- I am aware of no particular 'clause' (I think you mean conjunction or conclusive phrase ) that need be put at the end of a body paragraph (this would make the sequence of paragraph endings rather boring). You must simply complete the subtopic, but this does not necessarily require a such a word or phrase. There are a number of conclusive conjunctions and phrases which are available for use when appropriate, of course-- of which you have mentioned two: the result is and therefore .
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