The sum of kinetic energy and potential energy within a system is called a) thermal energy. b) chemical energy. c) electrical energy. d) mechanical energy.

D) Mechanical Energy

the national environmental policy act (nepa) is a united states environmental law that promotes the enhancement of the environment and established the president's council on environmental quality (ceq). the law was enacted on january 1, 1970. to date, more than 100 nations around the world have enacted national environmental policies modeled after nepa.