If there were more free states than slave states, then there would be a push for a factory-style economy. The South didn’t want this, as their economy was heavily dependent on slave labor. Basically, they wanted a balance between free and slave states so as to preserve their economy.
The Tenth Amendment or also referred to as Amendment X in simple terms is "Any power that is not given to the federal government is given to the people or the states." Hope this helps.
These surfaces radiate heat, causing air temperatures around the city to rise. Even after the sun sets each day, the surfaces hold onto their heat, making it more difficult for the temperature in the city to decrease.