An indirect effect of an action, be it a cost or benefit, for a third party who did not agree to the action is known as

externality

Explanation:

this is a pretty popular question but it is basically the definition of this word

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.

could you show the options for the answers? : )