Answer: At the federal level, environmental statutes establish standards that may be enforced by federal administrative agencies or by state agencies implementing federally approved state programs. State standards are sometimes more stringent than required by federal law, but they are never more lenient.
Explanation: For example, states may choose to establish and enforce their own programs consistent with the Clean Air Act (CAA) and the Clean Water Act (CWA). If they do not, those standards will be enforced by the U.S. Environmental Protection Agency (EPA), which also enforces the Resource Conservation and Recovery Act (RCRA), and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund). All of these laws are explained in greater detail on the EPA website, which also contains links to corresponding state laws. The National Historic Preservation Act (NHPA) establishes incentives to protect historic and cultural resources, while state and local historic preservation laws may actually restrict physical changes to property.
The Hellenistic Erasistratus discovered the heart was the pump to push blood through the arteries.
Aristarchus developed the theory that the sun was the center of the universe.
Euclid wrote the basic geometry book, Elements, that was used for 2000 years.
Hero of Alexandria devised the first steam engine although he considered it merely a toy.
Feudalism was the system in European medieval societies of the 10th to 13th centuries CE whereby a social hierarchy was established based on local administrative control and the distribution of land into units.
The French and Indian War began in 1754 and ended with the Treaty of Paris in 1763. The war provided Great Britain enormous territorial gains in North America, but disputes over subsequent frontier policy and paying the war's expenses led to colonial discontent, and ultimately to the American revolution
