The russian plain is also known by which of the following names

The Russian plain is also known by the name East  European Plain.

the Russian plain is the largest mountain - free area of Russia. This Eastern European plain stretches from eastern Poland to the Ural Mountains and encompasses all the Baltic countries, Belarus, most of Ukraine, and parts of western Russia.  The entire region referred to as the Russian plain is lower than 1,500 feet in elevation.

It extends over nearly 1,500,000 square miles and averages about 560 feet (170 m) in height. The plain is subdivided  into a number of distinct  geographical regions.

tension is the type of stress that results when two tectonic plates diverge .

explanation:

i think the reason that they immagrated was to find freedom of religion