Final answer:
The Middle Atlantic States have fertile soil due to a combination of factors, including the region's history of prosperous agriculture, the development of a vibrant folk culture influenced by diverse cultural inputs, and the deposit of nutrients from river valleys and yearly flooding.
Step-by-step explanation:
The Middle Atlantic States have fertile soil due to a combination of factors. One factor is the region's history of prosperous small-scale agriculture, which led to the development of fertile soils. Another factor is the diverse cultural inputs in the region, which contributed to the development of a vibrant folk culture that influenced agriculture. Additionally, the presence of river valleys and yearly flooding in some areas of the region also contributes to the deposit of nutrients in the soil, making it fertile.