Which of the following best explains why secondary sources are important to historians

the language dates from the contacts of arabian traders with the inhabitants of the east coast of africa over many centuries. under arab influence, swahili originated as a lingua franca used by several closely related bantu-speaking tribal groups.

the results of roman expansion produced social conflict and civil war. julius caesar gained power and became a dictator but was then assassinated. the reign of augustus began a long period of imperial rule and peace in the roman empire. rome faced the problems of how to maintain peace, law, and order.

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