Which event forced Chinese Communists and Nationalists to join forces?

The separation of northern ireland from the republic of ireland is an example of

(10 points) 1. cone 2. rectangle 3. triangle 4. circle 5. cylinder a. perpendicular cross section of a pyramid b. perpendicular cross section of a cylinder c. parallel cross section of a sphere d. shape created when a rectangle is rotated about the y-axis e. shape created when a right triangle is rotated about the y-axis

What are mountains that divide european russia from asian russia?