Final answer:
Pesticides must be registered by the U.S. EPA before they can be sold or used in the United States; this is regulated under FIFRA.
Step-by-step explanation:
Before a pesticide can be sold or used in the United States, it must be registered by the U.S. EPA. The Environmental Protection Agency (EPA) administers the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which predates the establishment of the agency itself, and maintains regulatory authority over the registration of all pesticides in the country. This ensures that pesticides are evaluated for their environmental impact, effectiveness, and potential harm to human health before they are authorized for use.