Final answer:
Genghis Khan's leadership was exceptional as he united Mongolian tribes under a single empire, fostered meritocracy, promoted religious tolerance, and created a unique military structure to ensure loyalty and effectiveness.
Step-by-step explanation:
Genghis Khan's leadership was distinct in several ways. He united the nomadic tribes of Mongolia into a single Mongol Empire, replacing aristocratic titles with a merit-based system and breaking down traditional societal structures. Genghis Khan introduced the yassa, a legal code that established public trials and held all Mongols, including himself, accountable. He decentralized the army by creating a nontribal decimal structure, dividing soldiers into groups of 10, 100, 1,000, and 10,000; each group lived and fought together, cultivating loyalty and coherence. Additionally, he promoted religious tolerance within his diverse empire, employing advisors from various faiths and elevating merit over background or creed.
Therefore, the correct answer to what made Genghis Khan's leadership different from previous leaders is: c) He united the tribes of Mongolia, recorded Mongolian laws and customs in the Mongol language, and created a nontribal decimal structure of conscription.