According to the mayflower compact why did the colonist at plymouth need to form a civil body politic

The Mayflower Compact was an agreement signed by the male passengers of the Mayflower and which served as the foundational governing agreement of the Plymouth colony. The Compact said that it was necessary to form a 'civil body politic' so that the colonists could be 'better ordered', or organized, to accomplish their shared goal of establishing an English colony in North America, and so that they would have the basis for establishing whatever laws, ordinances and offices they found necessary for accomplishing that goal.

The Calvert family is the answer

The Calvert family, which controlled Maryland, and the Penn family, which controlled Pennsylvania, decided in 1750 to engage two surveyors, Charles Mason and Jeremiah Dixon, to establish a boundary. They surveyed what became known as the Mason–Dixon Line, which became the boundary between the two colonies