what was the ‘time of trouble'? a. the reign of ivan the terrible b. the reign of the romanov family c. the period of time when russia faced continual mongol attacks d. a period when neither nobles nor aristocrats could decide on a russian ruler

d. a period when neither nobles nor aristocrats could decide on a russian ruler.

Explanation: The time of troubles started after the death of Fyodor in 1598 and lasted until the Romanov dynasty took over in 1613. During this period, there was a lack of leadership and several factions rose to install a new king. Men who claimed to be heirs to Dmitry also contested the throne at different times during this period. In addition, the country was at war with Poland and there were uprisings from peasants due to a 2-year long famine.

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof