Why are the continental divide and the fall line two important physical features in the united states?

The continental divide is important because it determines which direction rivers flow from their headwaters since it is at this divide point that water either flows one way or another so this explains where the important rivers flow ie say the Mississippi or Missouri. The fall line is where two parallel rivers drop down from a height of land so most likely would prevent navigation of the river at this point.

May consider a group  g=({0,1},+)g=({0,1},+)where  ++  will work as the xor operator like we work in boolean algebra. note here, that ‘00’ and ‘11’ are not the usual 0 and 1 that we work with everyday. the elements are  called  ‘00’ and ‘11’ and  may not mean  zero (nothing) and one (single). ‘00’ is the identity for the given binary operator +, meaning that any element operated with ‘00’ gets us that element itself.  for a set  ss  in  g′g′  having more elements than just  {0,1}{0,1}  the values for  a+b∈sa+b∈s, such that  a∈s,b∈sa∈s,b∈s, have to be first defined, only then can you determine the value of  1+11+1. the answer could possibly have been  22  if oanswer is25,000

It is c. naturally in the environment