National legislatures are formal bodies of elected representatives responsible for making laws and overseeing the government. They play a crucial role in shaping national policies and ensuring that the interests of citizens are represented. Examples of national legislatures include the United States Congress and the Parliament of the United Kingdom. These institutions typically consist of two chambers, such as a lower house and an upper house, although some countries have a unicameral system with only one legislative body. National legislatures also have the power to approve budgets, ratify treaties, and conduct investigations into government activities.