Here’s the answer :
Following a failed invasion of Iraq in 686, Abd al-Malik focused on securing Syria before making further attempts to conquer the greater part of the Caliphate from his principal rival, the Mecca-based caliph Abd Allah ibn al-Zubayr.
The burden of proof was put on Mexican Americans to prove that they owned the land.
Hope this is the right answer because Mexicans couldn't prove much.
Answer:
A widespread occurrence of an infectious disease in a community at a particular time.
Explanation: