Problem: Glass:

In physics, the standard definition of a glass (or vitreous solid) is a solid formed by rapid melt quenching. The term glass is often used to describe any amorphous solid that exhibits a glass transition temperature Tg. If the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the supercooled liquid is frozen into the solid state at Tg. The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory. Generally, the structure of a glass exists in a metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase.

What predicts glass-forming ability?
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A: rigidity theory

Problem: Chinese characters:

The art of writing Chinese characters is called Chinese calligraphy. It is usually done with ink brushes. In ancient China, Chinese calligraphy is one of the Four Arts of the Chinese Scholars. There is a minimalist set of rules of Chinese calligraphy. Every character from the Chinese scripts is built into a uniform shape by means of assigning it a geometric area in which the character must occur. Each character has a set number of brushstrokes; none must be added or taken away from the character to enhance it visually, lest the meaning be lost. Finally, strict regularity is not required, meaning the strokes may be accentuated for dramatic effect of individual style. Calligraphy was the means by which scholars could mark their thoughts and teachings for immortality, and as such, represent some of the more precious treasures that can be found from ancient China.

What is the art of writing Chinese characters?
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A: Chinese calligraphy

Problem: Federal Bureau of Investigation:

The FBI director is responsible for the day-to-day operations at the FBI. Along with his deputies, the director makes sure cases and operations are handled correctly. The director also is in charge of making sure the leadership in any one of the FBI field offices is manned with qualified agents. Before the Intelligence Reform and Terrorism Prevention Act was passed in the wake of the September 11 attacks, the FBI director would directly brief the President of the United States on any issues that arise from within the FBI. Since then, the director now reports to the Director of National Intelligence (DNI), who in turn reports to the President.

Who is responsible for briefing the FBI director?
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A: unanswerable

Problem: Carnival:

Three main parades take place during Carnival. The first is held on the first day, during which the "Carnival King" (either a person in costume or an effigy) rides through the city on his carriage. The second is held on the first Sunday of the festival and the participants are mainly children. The third and largest takes place on the last day of Carnival and involves hundreds of people walking in costume along the town's longest avenue. The latter two parades are open to anyone who wishes to participate.

Which of the festivals is comprised of participants who are mainly children?
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A:
The second