What lead to the downfall of the Umayyads?

Although this dynasty doomed to downfall after a centaury but the factors behind its downfall was present at the time of its beginning and politics of the alter caliphs and their corruption increased it. The main cause of the downfall of the Umayyads dynasty was the one man leadership instead of Islamic caliphate.

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