10. What were the motivations and goals for the mass
murders/genocides that occurred in the Soviet Union, China, and
Cambodia?

The motivations were mostly political and were done by the communist regimes established in those countries, with purpose of detaining their political enemies.

Explanation:

In all of these countries in different period totalitarian regimes were established. As the regimes were strict they opposed every possibility of opposition in that country. The most notable example are the mentioned ones, although only in Soviet Union millions of people were killed during Stalin's regime.

yes

explanation:

the term is einsatzgruppen