What state was the site of most battles of the civil war?

Virginia

Explanation:

Most of the battles in the Eastern Theater of the Civil War took place in Virginia because the Confederacy had to defend its national capital at Richmond. By the time General Robert E. Lee surrendered in 1865, much of the state had been ravaged by war.

C) Contagious diseases spread to both Europe and the Americas

Explanation:

The Columbian Exchange had many positives for both sides of the Atlantic, but unfortunately it had some negatives too. The biggest negatives were the spreading out of diseases. Both in Europe and the Americas, multiple diseases were brought from the other side, and they had devastating effects. The Europeans were affected but not to a degree to become almost extinct, while the Native Americans almost died out totally because of the diseases brought by the Europeans.