Misc: What country contains the greater lengths of the Tigris and Euphrates rivers?

Questions

City in northeastern Germany, capital of a United Germany from 1871 to 1945 & again since 1990?

City in western California, coextensive with San Francisco County?

City, capital of Nepal, in the central part of the country?

City, capital of the province of Quebec, Canada, in Quebec county, at the confluence of the Saint Lawrence & Saint-Charles rivers, in the southern part of the province?

Class of complex chemical compounds in plants?