What did west africans trade to north africans in exchange for salt? (1 point)
a. camels
b. gold
c. silver
d. masks

Iwill be giving 15 points to whoever answers the concept of checks and balances means that each branch of governmenta. has its own powers and responsibilitiesb. is clearly described in articles of the constitutionc. has the ability to correct the other branches in case of an errord. is set up so that in case of constitutional crisis, the governement will continue to operate

List three reasons why explorers began to explore new, and old areas. [[ps: doesn't explicitly say where. i think it's more in general.

Me i really need 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