Astudent reported that a limp stalk of celery became crisp when placed in ice water this is an example of a/an

The answer is an observation

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.