How did the custom of segregation replace the line drawn between slave and free before the civil war? Help me please!

When the united states entered world war ii it affect the lives of americans in many ways people were asked to such as food oil and gas the government awesome cars to purchase a to the country financially during the war more more working in all industries during the war

What is the most famous discovery attributed to isaac newton ? a) barometer b) thermometer c) laws of universal gravitation d) telescope

Why is it useful for historians to base certain studies on the analysis of historical periods