What lead to the fell of the Sahara trade

North Africa had declined in both political and economic importance, while the Saharan crossing remained long and treacherous. However, the major blow to trans-Saharan trade was the Battle of Tondibi of 1591–92.

Explanation:

The golden age of the trans-Saharan trade ended with the collapse of Songhay empire after the Moroccan attack in 1591.

Explanation:

The disintegration of West African political structures, the contemporary economic decline of Northern Africa, and the European competition on the Guinea coast made the caravan trade less profitable.

christopher columbus (1492–1504)

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation: