Amebas are single-celled organisms that need to obtain food in order to A. release oxygen into the air
B. protect themselves from other living
things
C. get the energy they need to carry
out life functions
D. remove harmful chemicals from the
environment

the answer is a or when it says crossing over

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.