Problem: Israel:

At the end of the 1990s, Israel, under the leadership of Benjamin Netanyahu, withdrew from Hebron, and signed the Wye River Memorandum, giving greater control to the Palestinian National Authority. Ehud Barak, elected Prime Minister in 1999, began the new millennium by withdrawing forces from Southern Lebanon and conducting negotiations with Palestinian Authority Chairman Yasser Arafat and U.S. President Bill Clinton at the 2000 Camp David Summit. During the summit, Barak offered a plan for the establishment of a Palestinian state. The proposed state included the entirety of the Gaza Strip and over 90% of the West Bank with Jerusalem as a shared capital, although some argue that the plan was to annex areas which would lead to a cantonization of the West Bank into three blocs, which the Palestinian delegation likened to South African "bantustans", a loaded word that was disputed by the Israeli and American negotiators. Each side blamed the other for the failure of the talks.

Who was elected Prime Minister in 1999?
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A: Ehud Barak


Problem: Kievan Rus%27:

It is not clearly documented when the title of the Grand Duke was first introduced, but the importance of the Kiev principality was recognized after the death of Sviatoslav I in 972 and the ensuing struggle between Vladimir the Great and Yaropolk I. The region of Kiev dominated the state of Kievan Rus' for the next two centuries. The Grand Prince ("velikiy kniaz'") of Kiev controlled the lands around the city, and his formally subordinate relatives ruled the other cities and paid him tribute. The zenith of the state's power came during the reigns of Vladimir the Great (980–1015) and Prince Yaroslav I the Wise (1019–1054). Both rulers continued the steady expansion of Kievan Rus' that had begun under Oleg.

What year did Sviatoslav pass away?
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A: 972


Problem: Copper:

Compounds that contain a carbon-copper bond are known as organocopper compounds. They are very reactive towards oxygen to form copper(I) oxide and have many uses in chemistry. They are synthesized by treating copper(I) compounds with Grignard reagents, terminal alkynes or organolithium reagents; in particular, the last reaction described produces a Gilman reagent. These can undergo substitution with alkyl halides to form coupling products; as such, they are important in the field of organic synthesis. Copper(I) acetylide is highly shock-sensitive but is an intermediate in reactions such as the Cadiot-Chodkiewicz coupling and the Sonogashira coupling. Conjugate addition to enones and carbocupration of alkynes can also be achieved with organocopper compounds. Copper(I) forms a variety of weak complexes with alkenes and carbon monoxide, especially in the presence of amine ligands.

Coupling products can be made by substituting Gilman reagent with what?
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A: alkyl halides


Problem: Solar energy:

Beginning with the surge in coal use which accompanied the Industrial Revolution, energy consumption has steadily transitioned from wood and biomass to fossil fuels. The early development of solar technologies starting in the 1860s was driven by an expectation that coal would soon become scarce. However, development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum.

What slowed the development of solar technologies in the early 20th century?
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A:
increasing availability, economy, and utility of coal and petroleum