Final answer:
The need for labor in the New World colonies and the practicality of acquiring slaves through trade with Africans were the most important factors in the establishment of the transatlantic slave trade.
Step-by-step explanation:
The most important factor in the establishment of the transatlantic slave trade was the need for labor in the New World colonies. As the demand for labor grew, Europeans realized that acquiring slaves through trade with Africans was the most practical method. Europeans set up trading posts along the coast of Africa, where captives were processed as cargo and then transported on the Middle Passage to the Americas. The slave trade transformed the economic way of life in the Americas, particularly on sugar plantations, where the majority of enslaved people were used as forced labor.
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