This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet. These sheets were cut into smaller window panes with nonuniform thickness, typically with the location of the pour centered in one of the panes (known as "bull's-eyes") for decorative effect. Modern glass intended for windows is produced as float glass and is very uniform in thickness. Question: How was the bull's-eye used?
for decorative effect

Passage: Switzerland is one of the richest and wealthiest countries in the world. Switzerland ranks top or close to the top in several metrics of national performance, including government transparency, civil liberties, quality of life, economic competitiveness, and human development. It has the highest nominal wealth (financial and non-financial assets) per adult in the world according to Credit Suisse and the eighth-highest per capita gross domestic product on the IMF list. Zurich and Geneva have each been ranked among the top cities with the highest quality of life in the world, with the former ranked 2nd globally, according to Mercer. Question: What is Switzerland's ranking for per capita gross domestic product on the IMF list?
eighth-highest

Passage: Important fragments survived from the mosaic floor of the Great Palace of Constantinople which was commissioned during Justinian's reign. The figures, animals, plants all are entirely classical but they are scattered before a plain background. The portrait of a moustached man, probably a Gothic chieftain, is considered the most important surviving mosaic of the Justinianian age. The so-called small sekreton of the palace was built during Justin II's reign around 565577. Some fragments survive from the mosaics of this vaulted room. The vine scroll motifs are very similar to those in the Santa Constanza and they still closely follow the Classical tradition. There are remains of floral decoration in the Church of the Acheiropoietos in Thessaloniki (5th6th centuries). Question: When were the mosaics at the church in Thessaloniki created?
5th6th centuries