Problem: In paintings, Mary is traditionally portrayed in blue. This tradition can trace its origin to the Byzantine Empire, from c.500 AD, where blue was "the colour of an empress". A more practical explanation for the use of this colour is that in Medieval and Renaissance Europe, the blue pigment was derived from the rock lapis lazuli, a stone imported from Afghanistan of greater value than gold. Beyond a painter's retainer, patrons were expected to purchase any gold or lapis lazuli to be used in the painting. Hence, it was an expression of devotion and glorification to swathe the Virgin in gowns of blue.
What rock was used as the source of blue pigment in paints in Medieval and Renaissance Europe?
The answer is the following: lapis lazuli

Problem: Mosaic art also flourished in Christian Petra where three Byzantine churches were discovered. The most important one was uncovered in 1990. It is known that the walls were also covered with golden glass mosaics but only the floor panels survived as usual. The mosaic of the seasons in the southern aisle is from this first building period from the middle of the 5th century. In the first half of the 6th century the mosaics of the northern aisle and the eastern end of the southern aisle were installed. They depict native as well as exotic or mythological animals, and personifications of the Seasons, Ocean, Earth and Wisdom.
When was the most important Byzantine church re-discovered?
The answer is the following: in 1990

Problem: Written Japanese also includes a pair of syllabaries known as kana, derived by simplifying Chinese characters selected to represent syllables of Japanese. The syllabaries differ because they sometimes selected different characters for a syllable, and because they used different strategies to reduce these characters for easy writing: the angular katakana were obtained by selecting a part of each character, while hiragana were derived from the cursive forms of whole characters. Modern Japanese writing uses a composite system, using kanji for word stems, hiragana for inflexional endings and grammatical words, and katakana to transcribe non-Chinese loanwords as well as serve as a method to emphasize native words (similar to how italics are used in Romance languages).
What uses a composite system?
The answer is the following: Modern Japanese writing

Problem: London has numerous venues for rock and pop concerts, including the world's busiest arena the o2 arena and other large arenas such as Earls Court, Wembley Arena, as well as many mid-sized venues, such as Brixton Academy, the Hammersmith Apollo and the Shepherd's Bush Empire. Several music festivals, including the Wireless Festival, South West Four, Lovebox, and Hyde Park's British Summer Time are all held in London. The city is home to the first and original Hard Rock Cafe and the Abbey Road Studios where The Beatles recorded many of their hits. In the 1960s, 1970s and 1980s, musicians and groups like Elton John, Pink Floyd, David Bowie, Queen, The Kinks, The Rolling Stones, The Who, Eric Clapton, Led Zeppelin, The Small Faces, Iron Maiden, Fleetwood Mac, Elvis Costello, Cat Stevens, The Police, The Cure, Madness, The Jam, Dusty Springfield, Phil Collins, Rod Stewart and Sade, derived their sound from the streets and rhythms vibrating through London.
What in part inspired the sounds of many British rock bands and singers in the 60s, 70s, and 80s?
The answer is the following:
the streets and rhythms vibrating through London.