Answer:
Hydrogen could become a future energy source as it can be used to create steam, electricity and other forms of energy. Hydrogen is also considered a clean form of energy, as its only product is water, which is harmless.
Explanation:
D) selecting random sample allows for a more representative sample in a survey.
Federalism is the division of power between states and the federal government.
Federal law preempts state law. This is due to the National Supremacy Clause in Article 6 of the U.S. Constitution.