Final answer:
The emergence of new Christian churches has had the greatest impact on the practice of Christianity since its standardization.
Step-by-step explanation:
The emergence of new Christian churches has most affected the practice of Christianity since the standardization of Christian beliefs. This change led to the formation of different denominations within Christianity, each with its own interpretations and practices. Examples of these new churches include the Protestant Reformation, which challenged certain aspects of Catholicism, and the rise of Eastern Orthodox churches in the Byzantine Empire.
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