Answers:

1. Monetary units: ruble and kopeck.
2. Most popular symbols: horseman with a spear, crown, and Saint George striking down a serpent.
3. These symbols were used to represent rulers, their power, and the country's history.
4. The origin of the word "ruble" is from the Russian verb "рубить" (rubit), meaning to chop. Historically, a ruble was a piece of a certain weight chopped off a silver ingot or grivna. Another version of the word's origin is it comes from the Russian noun "рубцу" (rubets), i.e. the seam that is left around the coin after casting.
5. The ruble was the Russian equivalent of the mark, a measurement of weight for silver and gold used in medieval Western Europe.
6. The folk name for ruble, "целковый" (tselkovy), means a wholesome, uncut ruble.
7. Russian history is reflected in a kopeck through the image of a horseman with a spear, which was later replaced by the image of Saint George striking down a serpent, representing the country's evolving identity and values.
8. In 1704, Russia was the first country in the world to introduce a decimal monetary system, where one ruble was equal to 100 kopeks.