<span>The
Amur river became the current boundary between Russian and Chinese
lands in 1858 with the treaty of Aigun, reversing the 1689 treaty of
Nerchinsk in which Russia cede the north bank to Qing china. Hope this helps you!!</span>
the spreading of one country to another
Answer:
This is called a culture region
Explanation:
<span>THE ANSWER IS MID-OCEAN RIDGES!!!</span>
