Final answer:
Legislative oversight is an example of an informal practice in the U.S. federal system of government.
Step-by-step explanation:
An example of an informal practice that emerged in the U.S. federal system of government is the development of legislative oversight. Legislative oversight refers to the practice of Congress monitoring and reviewing the actions of the executive branch to ensure they are in line with constitutional authority and legislative intent. While not explicitly mentioned in the Constitution, legislative oversight has become an important part of the federal government's checks and balances.
Learn more about Informal practices in the U.S. federal system of government