Answer:
the Abbasids
Explanation:
In 750, the Abbasids, a rival clan to the Umayyads, rose to power and overthrew the Umayyad Caliphate. They took control and formed the Abbasid Caliphate which would rule much of the Islamic world for the next several hundred years.
The assassination of Franz Ferdinand is what started WW1, which was done by Serbian rebels, but the county was Austria-Hungary. The two nations that escalated the conflict was Russia, who supported Serbia, and Germany, who supported Austria.
A)a new defensive tactic known as trench warfare
Trench warfare allowed the war to drag on for long periods of time because of the stalemates that ensue from the opposing armies refusing to give up the land under their controls, resulting in high casualties in no man's land.
Hope this helps
I believe it is the second one.
It provided a source of power for many kinds of machines.
Subject to their husbands and fathers seems to be the most fit answer :)
