Final answer:
The most significant change to the legal status of Africans in North America was the legislation that declared slavery as a hereditary condition.
Step-by-step explanation:
The law that caused the greatest change to the legal status of Africans in North America involved the declaration of slavery as a hereditary condition. Legislation passed during the 1660s in Virginia and Maryland transformed American slavery by making it a permanent condition passed down through generations, diverging significantly from African norms where slavery was neither inherited nor lifelong. This legal shift cemented the dehumanizing treatment of enslaved Africans and their descendants, setting a precedent for race-based, hereditary enslavement that would persist for centuries in the Americas.