They are important because without them there would be chaos. Checks and balances is basically checking on the others. The separation is for the three branches(Executive, Legislative, Judiciary) , each have the power to do their own duty; so there would not be just ONE person who takes over.
Marin Preda wrote Morometii
:)
Do you mean in the Soviet flag? If so here is your answer.
Answer: Communist symbol, hammer for industrial labors, and the sickle stands for the peasantry.