I thinks it’s either C or D. I’m not sure!
The Supremacy Clause (Article 6, Clause two) declares that the Constitution is the "supreme law of the land". It establishes that federal laws rule over state laws. This ensures that there will be no disagreement between the state and the national government over who has more authority. Federalism is a system of government where the power is shared between the state and national government, but this does not mean that they are equal. The national government will be "supreme".
Answer:
A prolonged war and greatly increased the number of casualties in the war
Explanation:
In World War I we saw the introduction of chemical weapons, machine guns, artillery, and tanks. All of this resulted in trench warfare and the lack of tactics to fight the new weapons meant that the war would be longer and a lot deadlier than it would have been without those weapons. It dragged for years from one stalemate to another and claimed a lot of lives.