Final answer:
The middle colonies were dubbed the 'bread basket' due to their extensive grain production, fertile soil, and leading role in the grain trade, which supported their rapid economic growth.
Step-by-step explanation:
The middle colonies were known as the "bread basket" because of their significant production of grain products, including wheat and flaxseed. This nickname reflects the region's agricultural productivity, which was facilitated by its long growing season and fertile land. Farmers in these colonies were able to sell their grain to both local and international markets, largely contributing to their economic growth. Additionally, the middle colonies experienced rapid economic growth due to the expansion of industries, such as shipbuilding and livestock, which were complementary to the grain trade.
The middle colonies were known as the "bread basket" because they were major producers of grain, especially wheat and flaxseed. The region had a long growing season and fertile land, which allowed farmers to grow a variety of crops and raise livestock. The middle colonies also had a strong merchant class and introduced technological innovations to lower shipping times, stimulating shipbuilding and its associated industries.