Which one of these protein structures shows the folding of the polypeptide which is held in place by interactions between r groups by h, ionic, and covalent bonds as well as strong disulfide linkages.

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.