On July 21, 1861, the Union and Confederacy fought at A. antietam
B. first battle of bull run
C. chancellorsvill

b

Explanation:

The first battle of bull run

hope that helps

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.

this is a good question! i'll do some research and come back when i have the answer!