Question: In the 20th century, Greek composers have had a significant impact on the development of avant garde and modern classical music, with figures such as Iannis Xenakis, Nikos Skalkottas, and Dimitri Mitropoulos achieving international prominence. At the same time, composers and musicians such as Mikis Theodorakis, Manos Hatzidakis, Eleni Karaindrou, Vangelis and Demis Roussos garnered an international following for their music, which include famous film scores such as Zorba the Greek, Serpico, Never on Sunday, America America, Eternity and a Day, Chariots of Fire, Blade Runner, among others. Greek American composers known for their film scores include Yanni and Basil Poledouris. Notable Greek opera singers and classical musicians of the 20th and 21st century include Maria Callas, Nana Mouskouri, Mario Frangoulis, Leonidas Kavakos, Dimitris Sgouros and others.
Is there an answer to this question: Who is one of the notable Greek opera singers in the 20th century?

Answer: Maria Callas

Question: By the definition most commonly used by linguists, any linguistic variety can be considered a "dialect" of some language"everybody speaks a dialect". According to that interpretation, the criteria above merely serve to distinguish whether two varieties are dialects of the same language or dialects of different languages.
Is there an answer to this question: According to the least used definition, what does everyone speak?

Answer: unanswerable

Question: Color in glass may be obtained by addition of electrically charged ions (or color centers) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses). Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber color from a reducing combustion atmosphere. Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. When used in art glass or studio glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures and 'cook' times. Most colored glass used in the art market is manufactured in volume by vendors who serve this market although there are some glassmakers with the ability to make their own color from raw materials.
Is there an answer to this question: What other additives can give glass a sulfur tint?

Answer: unanswerable

Question: The Early Cretaceous spans from 145 million to 100 million years ago. The Early Cretaceous saw the expansion of seaways, and as a result, the decline and extinction of sauropods (except in South America). Many coastal shallows were created, and that caused Ichthyosaurs to die out. Mosasaurs evolved to replace them as head of the seas. Some island-hopping dinosaurs, like Eustreptospondylus, evolved to cope with the coastal shallows and small islands of ancient Europe. Other dinosaurs rose up to fill the empty space that the Jurassic-Cretaceous extinction left behind, such as Carcharodontosaurus and Spinosaurus. Of the most successful would be the Iguanodon which spread to every continent. Seasons came back into effect and the poles got seasonally colder, but dinosaurs still inhabited this area like the Leaellynasaura which inhabited the polar forests year-round, and many dinosaurs migrated there during summer like Muttaburrasaurus. Since it was too cold for crocodiles, it was the last stronghold for large amphibians, like Koolasuchus. Pterosaurs got larger as species like Tapejara and Ornithocheirus evolved.
Is there an answer to this question: What dinosaur spread to every continent?

Answer:
Iguanodon