Final answer:
The Main Line started in Philadelphia and extended westward towards Harrisburg.
Step-by-step explanation:
The statement that The Main Line started in Harrisburg and was built eastward and westward from its city center is false. The Main Line is actually a term for the suburbs of Philadelphia served by the Pennsylvania Railroad's main line, which connected Philadelphia with points west. Therefore, it did not originate in Harrisburg, but rather in Philadelphia.
Concerning the constitution adopted by Pennsylvania, it is true that Pennsylvania adopted one of the most conservative constitutions of the Revolutionary Era. The constitution of 1790 sought to balance power more evenly than the previous constitution of 1776. Finally, it is worth mentioning that Francis Cabot Lowell indeed built the first integrated textile mill in New England, setting forth the foundation of the industrial revolution in the United States.