4. (5 points) The United States and the European Union have had a disagreement over the European Union's banning of imports of beef and pork from livestock (cattle and pigs) that have been fed growth hormones. Assuming that the U.S. livestock farmers feed the animals growth hormones, please explain how such a ban by the EU can be considered a non-tariff trade barrier? You must give an explanation. (Only typed answers are accepted)