Why did the Songhai Empire become economically successful?

Which of these was an accomplishment of the han dynasty? the invention of the seismograph finding a water passage to europe the invention of the ballpoint pen the invention of the abacus

Number these events in the order in which they occurred. union forces retreated. union forces launched a surprise attack. more confederate troops arrived by train.

With the start of each new era in japan the country‘s capital changed location, why? a. so the nobility would be able to retain power b. so the capital would be in the new leaders city c. to give each region of the country an opportunity to rule d. to accommodate shifts in the country’s population