How historians determine if a source is bias ?

Do you believe that unity of purpose and belief are what made the american colonies strong, or do you believe that societies whose citizens were compelled to interact with people of differing beliefs were the most successful, based on the history

Why did france demand that germany repay their debts in foreign currency?

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