When English settlers came to Jamestown, the living conditions were very poor. By the time 1609 had come around, they had faced a harsh winter called "the starving time".
Because the winter was so harsh, people were getting sick and dying off at a very fast rate. Only about 1/3 of the settlers survived that winter, and it was rumored that the starving time was so bad that the settlers turned to eating some of the animals, such as the dogs to stay alive.
Because the people were eventually reinforced with supplies and more settlers, the colony of Jamestown was able to persevere and keep going considering they lost a significant amount of their original settlers. The tobacco crop and more settlers coming on ships in the next few years is what was able to keep Jamestown thriving.
This helped make it the first permanent settlement in North America, unlike the Lost Colony of Roanoke, Virginia, where all the settlers had vanished in the late 1500s.
Because The Founding Fathers wanted a new constitution
Fighting until death and the survivor was free
