What clause in the constitution has been used by the federal government to extend its power at the expense of the states

Clause 18 from Article 1 Section 8

Explanation:

Clause 18 from Article 1 Section 8 granted the power to the government make all Laws which shall be necessary to carried out their main duties that is directly written on the constitution.

This single clause alone, granted so much flexibility for the government to create agencies and regulations that are not directly written/regulated for them within the constitution.

Example of the usage of this would be the creation The First and Second Banks of the United States, They does not necessarily written on the Constitution, but the government use it to control and regulate the economy of the nation as a whole.

they protect against unsafe foods and medicines being sold

explanation: