Tectonic activity happens when changes to the earth’s crust are caused by a. changes to the earth’s gravity b. changes to the earth’s temperature c. the movement of the earth’s plates d. the rising of the earth’s oceans

The Red Army (Krasnaya Armiya) was a common name for the Russian National Military Forces from 1918 to 1946, which was also known by the abbreviation RKKA (Workers’ and Peasants’ Red Army). The name refers to the color red. In the workers' movement red symbolized the blood shed in the struggle against oppression.

Please put it in your own words and sum it up, have a great day!