Judging by the historical records, by approximately 1000 AD the predominant ethnic group over much of modern European Russia, Ukraine and Belarus was the Eastern branch of the Slavs, speaking a closely related group of dialects. The political unification of this region into Kievan Rus' in about 880, from which modern Russia, Ukraine and Belarus trace their origins, established Old East Slavic as a literary and commercial language. It was soon followed by the adoption of Christianity in 988 and the introduction of the South Slavic Old Church Slavonic as the liturgical and official language. Borrowings and calques from Byzantine Greek began to enter the Old East Slavic and spoken dialects at this time, which in their turn modified the Old Church Slavonic as well.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What commercial language was adopted by Christians in 880?
Ah, so.. unanswerable

The typical image of migration is of northern landbirds, such as swallows (Hirundinidae) and birds of prey, making long flights to the tropics. However, many Holarctic wildfowl and finch (Fringillidae) species winter in the North Temperate Zone, in regions with milder winters than their summer breeding grounds. For example, the pink-footed goose Anser brachyrhynchus migrates from Iceland to Britain and neighbouring countries, whilst the dark-eyed junco Junco hyemalis migrates from subarctic and arctic climates to the contiguous United States and the American goldfinch from taiga to wintering grounds extending from the American South northwestward to Western Oregon. Migratory routes and wintering grounds are traditional and learned by young during their first migration with their parents. Some ducks, such as the garganey Anas querquedula, move completely or partially into the tropics. The European pied flycatcher Ficedula hypoleuca also follows this migratory trend, breeding in Asia and Europe and wintering in Africa.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Where do the dark-eyed junco migrate?
Ah, so.. arctic climates to the contiguous United States

Chopin's qualities as a pianist and composer were recognized by many of his fellow musicians. Schumann named a piece for him in his suite Carnaval, and Chopin later dedicated his Ballade No. 2 in F major to Schumann. Elements of Chopin's music can be traced in many of Liszt's later works. Liszt later transcribed for piano six of Chopin's Polish songs. A less fraught friendship was with Alkan, with whom he discussed elements of folk music, and who was deeply affected by Chopin's death.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What piece did Chopin dedicate to Schumann?
Ah, so..
Ballade No. 2 in F major