The answer would be sound waves.
Hope this helps!
During the period between 1775 and 180, many African Americans gained freedom from slavery, yet during the same period, the institution of slavery expanded. The changes took place in different locations in the United States of America. The Northern states opposed slavery while the Southern states still enforced slavery. Many African American slaves managed to escape from the South to the North where they were freed from slavery. The freed African-American slaves spent their time working towards helping the slaves in the Southern states escape towards the North. The slaves in the South were forced to work on the tobacco and cotton plantations. They bided their time until they were able to escape.
the spanish war is important because it was proably the first conflict that broke out and the native american indians won so it got important because it was the first time in years they had ever won a war
i believe the answer is c.
