Final answer:
One of the only external factors that is also relevant domestically is tariffs, which are taxes imposed on imported goods.
Step-by-step explanation:
One of the only external factors that is also relevant domestically is Tariffs. Tariffs are taxes imposed on imported goods, and they can impact trade both internationally and domestically. When a country imposes a tariff on imported goods, it increases the cost of those goods for domestic consumers, which can influence their purchasing decisions and potentially affect the domestic market.