What agency develops and enforces environmental regulations in the U.S.?

The Environmental Protection Agency (EPA) is the agency responsible for developing and enforcing environmental regulations in the United States. Established in 1970, the EPA's mission is to protect human health and the environment by creating regulations based on laws passed by Congress. This includes setting limits on pollutants, overseeing waste management, and ensuring that air and water standards are maintained to safeguard public health. The agency also conducts environmental assessments and research to inform its regulatory actions.

In the context of the other options, the FBI is primarily focused on national security and law enforcement, not environmental issues. The National Oceanic and Atmospheric Administration (NOAA) deals with weather, oceans, and atmospheric conditions but does not manage the broad spectrum of environmental regulations that the EPA handles. Lastly, the Department of Natural Resources (DNR) exists at the state level and focuses on local resource management, which is important but does not encompass the overall responsibility for national environmental regulations like the EPA does. Thus, the correct answer identifies the agency specifically tasked with environmental protection on a national scale.