Niger and Congo are two rivers after which countries are named (actually in both cases two countries each) - and those are African countries, so they must be in Africa.
Zambezi is a river in Angola and Namibia.
Tigris is a River in Mesopotamia, in Asia - so that's the correct answer!
Study a place without actually having to be there.
With a country as big as Russia, it is hard to give you an accurate estimation. Siberia is known for some of the coldest winters in the world, reaching a very dangerous -35 degrees Celsius. The north pole of cold has a record breaking -69 degree celsius winters. over 65% of Russia is covered by permafrost. There is a humid continental climate as well.
