A city has been building roof-top gardens, installing heat-reflecting roofs, and creating more parks. Which of the following environmental issues is the city most likely trying to overcome?

Two of these describe "federalism." (choose two answers) select one or more: a. the national government absolutely controls all state governments. b. power is shared by the national and state governments. c. state governments exercise absolute power over the national government. d. it is a compromise meant to eliminate the disadvantages of a "unitary" and a "confederate" system.