In the ancient world, why did civilizations flourish around great river valleys? A) River valleys protected citizens from natural disasters.
B) River valleys provided an ideal environment for agriculture.
C) River valleys sheltered citizens from harsh weather.
D) River valleys contained vast mineral resources.

B) River valleys provided an ideal environment for agriculture

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B or D depends on point of view

Explanation:

1) the answer is b

senators serve a six-year term; representatives serve a two-year term, making them more responsive to (and responsible for) voter confidence.

2) the answer is d

to serve as president, one must:   -be a natural-born u.s. citizen of the united states;   be at least thirty-five years old;   be a resident in the united states for at least fourteen years.

3) the answer is a

ella,because it is constitutionally eligible

4) the answer is c: the u.s president

me on my last question.