Besides rivers what other physical features are used to define state borders in the us

One disadvantage that darwin faces today is w. enemy attacks x. natural disasters y. lack of land bridge z. high population density

The distance a car travels between the time the driver decides to stop the car and the time the driver puts on brakes is called the reaction distance. how does the reaction distance change with speed? a.reaction distance decreases with with speed b.reaction distance stays the same with speed c.reaction distance increases with speed. d.there is not enough information to answer the question

What does the map above tell us about the endemity of typhoid fever