there is only one continent which is South America
On both the North and South American Continents.
Oceania
It is part of Oceania.
South America is one continent, and it does not have continents in it or on it because South America in itself is one big continent. There are countries in the continent of South America, but not continents.
Someone from South America would come from the continent South America. There are two continents by the name America, north America and south America.
Antarctica is south to all other continents. It is the only continent with no permanent inhabitants.
There are NO continents in South Africa. South Africa is one of the nations on the African continent.
None. It is firmly set within the North American continent (or the American continent, depending on the number of continents you are taught). It however, connects two regions within the North American continent: the United States to the north and Central America to the south. Note Central America is a region, not a continent.
North America
Antarctica is the continent south of all the others.
This depends on which side of the world you are on and what country you are in. If you are asking about the North American and South American continents, Canada is located in the North American continent.