Answer:
Britain has the largest coal reserve in Europe.
Step-by-step explanation:
During the earlier era of the industrial revolution, Coal was the primary source of energy fuel that people use to power their cities, factories, vehicles, etc.
Having the largest coal reserve means that Britain could make all the production/manufactures in the country become significantly cheaper. When they sell their products to the international market, this will resulted in higher profit for Britain. As a result, Britain become the most prosperous nation during the earlier era of Industrial Revolution.