What are the roles/powers of the president? List at least three.

 The Constitution explicitly assigns the president the power to sign or veto legislation, command the armed forces, ask for the written opinion of their Cabinet, convene or adjourn Congress, grant reprieves and pardons, and receive ambassadors.

The correct answer is B, as the factor that ended the Mongol rule of Russia was that Ivan III refused to continue paying tribute to the Golden Horde.

Before dying, Genghis Khan divided the Mongol Empire among his four sons. Jochi, the eldest, had died, so the portion he played (south of present-day Russia) was divided between his sons Batu, chief of the Blue Horde (east), and Orda, chief of the White Horde (west).

Batu managed to control the territory of Orda and subjugated the northern littoral of the Black Sea, incorporating the Turkic peoples of the area to his army. Between the end of the 1230s and the beginning of the next, he carried out a series of victorious campaigns against Volga Bulgaria and the successor states of Kievan Rus.

While the great Khan Ogodei and his successors completed the conquest of East Asia, the Mongols under Batu Khan went to Europe. In 1237, the armies of the Blue Horde plundered most of the cities of the Principality of Vladimir-Suzdal. Three years later they did the same with Kiev; going west, after the battles of Legnica and Mohi, they entered Poland, Bohemia, Hungary and the Danube valley, reaching the Adriatic coast.

The Russians paid no attention to the warnings of the first Mongol incursions, and that is why the invasion of Russia by the Mongols came to them by surprise. The Mongols were no longer a nomadic horde but the Russians were now facing a Sino-Mongolian army that had learned the advanced Chinese military sciences as well as the war traditions of Central Asia. The Mongol armies remained in the field throughout the year, and their siege methods relied heavily on Chinese skills and specialists.

On October 8, 1480, the Khan troops attempted to cross the river to the west of Nizhny Novgorod, near the confluence of the Oka River and the Volga but were rejected, the Russians according to the chronicle used firearms to stop them. For four days, the Tartars attempted to cross the river, but were repulsed and finally retreated to their capital Sarai, as the Crimean Khan threatened their rear. That was the first of a series of disasters that would lead to the disintegration of the Golden Horde. Several months later, the khan was killed by a rival and the Mongolian power suffered a new setback. The acts of Ivan freed the Russians to pay taxes and they were finally worth the independence.