Of the following, which contributes the most to climate change?

Of the following, which contributes the most to climate change?
 
  a. hydroelectric power
  b. coal and oil
  c. natural gas
  d. nuclear power

Question -2-

Which of the following demonstrates how policy making is decentralized in the United States?
 
  a. The United States has a unitary form of government.
  b. Congressional power often trumps state power.
  c. The states have authority over policy making in areas such as education.
  d. The federal government is responsible for Medicare and Medicaid.

Question -3-

What is the largest source of electrical power in the United States?
 
  a. coal
  b. oil
  c. natural gas
  d. nuclear power