QUES: Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.

Why are high-index glasses valued?
What is the answer?
ANS: for their diamond-like optical properties
QUES: A CD containing 20 musical selections from the game was available as a GameStop preorder bonus in the United States; it is included in all bundles in Japan, Europe, and Australia.[citation needed]

What is included in all selections?
What is the answer?
ANS: unanswerable
QUES: In addition to the cathedral, Strasbourg houses several other medieval churches that have survived the many wars and destructions that have plagued the city: the Romanesque Eglise Saint-Etienne, partly destroyed in 1944 by Allied bombing raids, the part Romanesque, part Gothic, very large Eglise Saint-Thomas with its Silbermann organ on which Wolfgang Amadeus Mozart and Albert Schweitzer played, the Gothic Eglise protestante Saint-Pierre-le-Jeune with its crypt dating back to the seventh century and its cloister partly from the eleventh century, the Gothic Eglise Saint-Guillaume with its fine early-Renaissance stained glass and furniture, the Gothic Eglise Saint-Jean, the part Gothic, part Art Nouveau Eglise Sainte-Madeleine, etc. The Neo-Gothic church Saint-Pierre-le-Vieux Catholique (there is also an adjacent church Saint-Pierre-le-Vieux Protestant) serves as a shrine for several 15th-century wood worked and painted altars coming from other, now destroyed churches and installed there for public display. Among the numerous secular medieval buildings, the monumental Ancienne Douane (old custom-house) stands out.

In what century was the Eglise Saint-Etienne constructed?
What is the answer?
ANS:
unanswerable