The Treaty of Tordesillas established an imaginary line running down the middle of the Ocean.
a.
Atlantic
c.
Indian
b.
Pacific
d.
Arctic

A. Atlantic

The Papal Division ran through the middle vertically in the Atlantic, don't mistake it for the Treaty of Saragossa, which is in the Pacific.

this act gave the federal government the power to relocate any native in the east to territory west of the mississippi river.