The correct answer to this open question is the following.
ONE specific environmental or geographical feature of the middle colonies that contributed to the region's unique development before 1754. was the fertile soil of the middles colonies, that allowed American farmers to grow good crash crops that were traded to the colonies and exported to Europe.
The middle colonies of Pennsylvania, New Jersey, Delaware, and New York, had such a fertile soil that were known as the breadbasket of America, for the good quality of crops that they produced. Exportations of the goods and raw materials were facilitated due to their harbors and connections to Europe.