What could a 21st century historian learn from this primary source

In the confederate states of america, the government could not overrule the decisions of state course. what happened to the states when they had conflicts?

Will have the greatest effect on human health. pollution in the a. troposphere b. stratosphere mesosphere d. thermosphere

At the time of the brown v. board of education decision,schools were segregated everywhere in the country.several states had laws requiring segregated schools.schools in nearly every state has been desegregated.segregation was common in the north, but not in the south.