Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

[Q]: Passage: The heat required for boiling the water and supplying the steam can be derived from various sources, most commonly from burning combustible materials with an appropriate supply of air in a closed space (called variously combustion chamber, firebox). In some cases the heat source is a nuclear reactor, geothermal energy, solar energy or waste heat from an internal combustion engine or industrial process. In the case of model or toy steam engines, the heat source can be an electric heating element. Question: Along with nuclear, geothermal and internal combustion engine waste heat, what sort of energy might supply the heat for a steam engine?
[A]: solar


[Q]: Passage: Contrary to popular belief, Genghis Khan did not conquer all the areas ultimately part of the Mongol Empire. At the time of his death, the Mongol Empire stretched from the Caspian Sea to the Sea of Japan. The empire's expansion continued for a generation or more after Genghis's death in 1227. Under Genghis's successor Ögedei Khan the speed of expansion reached its peak. Mongol armies pushed into Persia, finished off the Western Xia and the remnants of the Khwarezmids, and came into conflict with the imperial Song dynasty of China, starting a war that lasted until 1279 and that concluded with the Mongols gaining control of all of China. They also pushed further into Russia and eastern Europe. Question: Who led the most rapid expansion of the Mongol Empire?
[A]: Ögedei Khan


[Q]: Passage: As previously arranged by his father, Temüjin married Börte of the Onggirat tribe when he was around 16 in order to cement alliances between their respective tribes. Soon after Börte's marriage to Temüjin, she was kidnapped by the Merkits and reportedly given away as a wife. Temüjin rescued her with the help of his friend and future rival, Jamukha, and his protector, Toghrul Khan of the Keraite tribe. She gave birth to a son, Jochi (1185–1226), nine months later, clouding the issue of his parentage. Despite speculation over Jochi, Börte would be Temüjin's only empress, though he did follow tradition by taking several morganatic wives. Question: What year did Börte's give birth to Jochi?
[A]:
1185