Principle which explains that in a sequence of undeformed sedimentary rock, the oldest bed is on the bottom and each higher bed is successively younger, is called the principle of:

What is the most effective approach the government can take to keep the air clean? create and enforce regulations that limit fossil fuel burning by industries use funds to understand why smoke and mold are causes of outdoor air pollutants educate people about the threats to outdoor clean air from visible forms of air pollution modify regulations under the clean air act by including expensive options to reduce air pollution