Christians can be found in almost every country in the world. They are however not always welcome. I have read that things have become difficult for Christians in Muslim countries since the 911 attacks on the U.S. Persecution levels are high and in some Muslim countries they are still beheaded. Hope this helps. Everywhere, there are Christians all around the world, from every race and every nation. They live basically anywhere a normal person would live.
The US of A.
Yes, most of them are Christians.
Bulgaria
Poland
Jordan
egypt
Probably either India or the Philippines.
I assume you mean sub-saharan africa- and in that case it would be South Africa (the country).
The most popular religion in South Africa is Christianity (68% of the country are Christians)
South Africa has the most Christians. They practice this religion 4 times per week.
Approximately 65-70% of the population in Brazil identifies as Christian, with Catholicism being the largest denomination followed by various Protestant denominations. The country also has a growing number of Evangelical Christians.
The country with the most Christians on earth, at the present time, is China, estimates are around 60 to 75 million. It is only an estimate because many Christians in China attend "underground" or non-government approved churches.