Conversation so far:
in which 2 hemispheres is north america located
The United States is in both the Northern and Western hemispheres.
what countries are in the southern hemisphere
The Southern Hemisphere includes most of South America, one-third of Africa, all of Antarctica, a small sliver of Asia and all of Australia/Oceania.
what countries are in the western hemisphere
With more than 20 different countries, North America is a large and lively continent in the Western Hemisphere.
how many hemispheres are there total on earth
Any circle drawn around the Earth divides it into two equal halves called hemispheres. There are generally considered to be four hemispheres: Northern, Southern, Eastern, and Western.

Question: which continent is on all four
Self-contained rewrite: which continent is on all four hemispheres