What were some effects of the columbian exchange?

Some effects of the Colombian exchange were cultural diffusion. for example the europeans would take corn (something Europeans didnt have) from america back to europe. the columbian exchange was not all positive since europeans would bring diseases such as small pox back to america which eventually would cause many natives to die off 

The effects of the Columbian Exchange, were/are: Food for one because some of the favorite foods that we like today originated in a distant land. Few events transformed the world like the Columbian Exchange. The global transfer of plants, animals, disease, and food, brought together the eastern and the western hemisphere in touched, in some way, nearly all the people of the world.

Your answer is b , public works

12 days because 1/4 is 25% of 100 if 100 is equal to 1 pound then multiply 3 by 4 which equals 12