.All of the following are true about the Arab Empire EXCEPT—
they tolerated monotheistic religions as long as people paid a tax.
it was easily conquered because Islam is nonviolent.
its first leader was Muhammad.
people joined it after seeing its strong fighting force in action.

Except they tolerated monotheistic religions as long as people paid a tax.

Explanation:

The three major monotheistic religions, Judaism, Christianity, and Islam originated in what is known today as the Arab world and are still predominant with rare expetions of minority groups who are very often subjected to abuse and suppression of human rights, especially right to religion.

The Arab World, most particularly countries under current Arab empire had in pre-Islam period tradition of polytheistic religions.

separation of church and state? not sure what you mean.

the answer is blue river