Iguaçu falls lies on the border of which two countries?

Argentina and Brazil

Explanation:

The Iguacu river rises near the heart of the city of Curitiba. For most of it's course, the river flows through Brazil , however, most of the falls are on the Argentine side. below its confluence with the San Antonio River, the Iguacu river forms the boundary between Argentina and Brazil .

heat from the core of the earth causes convection currents to occur in the mantle. these currents slowly move the crust around.