(A) The expansion of railroad system
(B) ** An increase in steamship transportation
EXPLANATIONS BELOW
Concept note-1: -David Ricardo developed the classical theory of comparative advantage in 1817 to explain why countries engage in international trade even when one country’s workers are more efficient at producing every single good than workers in other countries.
Concept note-2: -If the ratio of trade to the GDP increases by 1 unit, the GDP per capita increases by 1895$ on average. International trade can provide better access to the newest technology and therefore, positively contribute to the future growth, which can be one of the explanations of the positive sign.
Concept note-3: -International trade allows countries to expand their markets and access goods and services that otherwise may not have been available domestically. As a result of international trade, the market is more competitive. This ultimately results in more competitive pricing and brings a cheaper product home to the consumer.
Concept note-4: -Foreign trade expands a country’s market for its products. Exports have the potential to boost national output and serve as a growth engine. Expansion of a country’s foreign trade may revitalise an otherwise dormant economy and lead it down the road to wealth and growth.