National border is the type of border among the following choices given in the question that would likely have the most protection. The correct option among all the options that are given in the question is the third option or the penultimate option. I hope the answer helps you.
The powers of Congress are affected by all of these options except the "state constitutions", since the Constitution gives Congress final authority over the states in terms of legislation.
The answer is A as river valley civilizations relied on rivers as a source of life. River valleys like Egypt, Mesopotamia and Xi, the rivers brought silt and made the soil very fertile, it also brought fresh water and fish to eat. People can also move fast using rivers.
