4.3 Human and physical influences on global interactions

The scenario eliminates import duty (a tariff), customs delays (a non-tariff barrier), and divergent product regulations (another non-tariff barrier). All three types of friction are removed simultaneously, which is the defining characteristic of deep integration.

The EU single market operates through the four freedoms: free movement of goods, services, capital, and labour. The free movement of goods specifically removes tariffs and harmonizes product standards across member states, covering every barrier named in the scenario.

The Schengen Agreement removes passport checks for people, not product tariffs or standards. The customs union focuses on the common external tariff applied to non-members. The eurozone removes currency conversion costs, not regulatory barriers to goods trade.

The EU single market is the correct framework because it combines tariff removal with regulatory harmonisation, allowing goods to cross internal borders as freely as within a single country — exactly as described in the scenario.

The question asks which specific EU policy allows a Warsaw manufacturer to sell in Lisbon without duty, delays, or separate product regulations. We need a framework that addresses all three barriers simultaneously.

The Schengen Agreement covers the free movement of people across borders by removing passport checks. It does not govern product standards, tariffs, or commercial trade regulations, so it cannot explain the scenario.

The customs union sets a common external tariff on goods entering the EU from outside member states. It does not deal with removing internal product regulations between member states — that is the role of the single market.

The eurozone eliminates exchange-rate risk by adopting a shared currency. The scenario involves a Polish firm (Poland retains the złoty) selling in Portugal, so the issue is regulatory and tariff barriers, not currency conversion — the eurozone is irrelevant here.

The EU single market is the only framework that simultaneously removes tariffs, customs delays, and divergent product standards through the four freedoms, making it the correct answer.

The scenario involves two distinct moments: (1) paying duty at Hamburg — the external EU border — and (2) moving goods freely to Austria and Czech Republic with no further charges. These two moments correspond to the two mechanisms of the EU customs union.

The EU customs union works through a common external tariff (CET), charged once at the point of entry into the EU. Once that tariff is paid and the goods clear customs, they are free to circulate anywhere in the EU without further customs duties — internal barriers are eliminated.

While the EU single market also facilitates free movement of goods, the specific mechanism here — paying duty once at the external border, then free internal circulation — is the defining feature of a customs union, not merely a free trade area or single market rule. The customs union removes the need for origin checks at internal borders.

The EU customs union — specifically its CET applied at the external border combined with zero internal customs duties — is the mechanism that explains why textiles from Bangladesh pay duty once at Hamburg and then move freely to Austria and Czech Republic.

We need to identify which EU trade policy mechanism allows goods from a non-EU country (Bangladesh) to move freely between EU member states after paying duties at the first port of entry.

The four freedoms apply to goods produced within the EU single market area. The scenario involves Bangladeshi goods — non-EU in origin — so the single market's rules on internal goods do not explain why duty is only charged once at the external border.

Schengen abolishes passport checks for people at internal borders. It does not govern customs duties or the movement of freight from non-EU countries. Schengen and customs union are entirely separate agreements.

USMCA is a North American free trade agreement that does not apply to EU trade. There is no USMCA-style preferential mechanism in the EU for goods from Bangladesh; this option is a fabricated distractor.

The EU customs union is correct: a common external tariff is applied once at Hamburg (the EU's external border), and the elimination of internal customs duties allows onward movement to Austria and Czech Republic without further charges.