Unrestricted submarine warfare
Answer:
Crossing rivers were probably the most dangerous thing pioneers did. Swollen rivers could tip over and drown both people and oxen. Such accidents could cause the loss of life and most or all of valuable supplies. Animals could panic when wading through deep, swift water, causing wagons to overturn.
Explanation:
The original thirteen colonies flourished and developed into what became the fifty US states, thanks to ample resources and opportunities. This country's political geography was the consequence of many treaties and conquests that resulted in the country reaching from the Atlantic to the Pacific Ocean.
