There was no single Islamic Empire, but assuming that you are referring to the Rashidun, Umayyad (Damascus), and Abbassid Caliphates, these were complex states with a large bureaucracy, numerous governates and more local regions, and a complex hierarchical leadership.
The Byzantine Empire was divided into numerous provinces and local rulers. It was complex.
By forming Islamic armies, conquering non-Islamic countries, and making them into Islamic countries. Simple.
There is no Islamic Empire.
The title of the Islamic Empire was Caliphate. The Caliph was called Amir-ul-Momineen.
It depends on the Islamic Empire in question. Assuming that you are talking about the Abbassid Caliphate (which is most commonly referred to as "the Islamic Empire"), the group that brought them down was the MONGOLS.
In 1492 the Islamic Empire finally left Spain but i dont know when it began.
The Alhambra is not a religion, but rather a palace and fortress complex located in Granada, Spain. It was constructed by the Nasrid dynasty of the Islamic empire and reflects Islamic architectural and artistic influences.
Yes. The Mughal Empire was a great Empire of the Muslims in India.
Ottoman Empire
Different in different parts of the empire.
The Abbasids, as the ones from the Islamic Empire.
There is no such thing as a simple complex carbohydrate. Carbohydrates are either simple or complex; they cannot be both.