Can someone help me with this?

Why did some states believe they had the power to overturn federal laws?

Which answer best describes an advantage of shipping goods by canal? a) most towns would rather have canals then noisy railroads b) goods could travel very fast downstream in the canal system c) traveling by boat is a much more relaxing way to transport goods. d) heavy loads of goods could travel by boat more easily then if pulled by horses.

Why did people from washington ride out to manassas junction to view the battle?