Final answer:
Imperial wars between Britain, France, and Spain led to greater unity among the 13 colonies in the 1700s.
Step-by-step explanation:
A second factor that led to greater unity among the 13 colonies during the first half of the 1700s was the imperial wars between Britain, France, and Spain. These wars exacerbated tensions between the colonies and the mother country, bringing their similarities into focus. The colonies realized that they faced common threats from external powers and needed to unite to protect their interests.