I think it is A B and C, but I am not completely sure, it might be B, C, and D.
Answer:
First prompt seems easy.
Explanation:
The most important impact of the Columbian Exchange was the spread of different animals and vegetables.
Now, you can come up with the rest by researching about the Columbian Exchange if you don't know much about it, instead of asking for someone to do the whole document for you. I got you starting line, you're welcome :)
Explanation:

appointment of a particular Government servant to a post was erroneous or not ... ability of the candidates under consideration. ... to be followed in such cases will be as given below.
What plans? No one can help you if you do t give the whole question