A is a set of interrelated propositions that attempt to describe, explain, predict, and ultimately control some class of events.

Theory

Explanation:

Theory is defined as concept tat determines about certain topic through content and idea .This explanation is continuously tested so that the phenomena explained through the concept can be appropriately accounted. Theories are not based on guesses.

The subject on which theory is described contains linked facts and statements for elaborating about the matter.Example of theories are atomic theory, evolution theory etc.  

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.

portugal is the westernmost country in europe.