What types of barriers might prevent trade between countries in economics?

Who introduced arabic numerals to italy, which make bookkeeping possible? a. brunelleschi b. cosimo de medici c. fibonacci d. gregory xi e. giovanni de bicci de medici

What were the immediate effects of prohibition? check all that apply. bootleggers illegally made and sold alcohol. corruption and crime increased. speakeasies were the only legal places to buy alcohol. crime and corruption decreased. alcohol sales were banned in the united states.

The picture below shows president richard nixon and the first lady standing before the great wall of china in 1972. they are smiling - as are the chinese with them. when this picture was shown on american television, americans were aware that it was a historic moment. what are two reasons why this moment was important for both china and the united states?