How well does the speaker use the aids?

Visual aids add impact and interest to a presentation. They enable you to appeal to more than one sense at the same time, thereby increasing the audience's understanding and retention level. With pictures, the concepts or ideas you present are no longer simply words - but words plus images.

Explanation:

Visual aids add impact and interest to a presentation. They enable you to appeal to more than one sense at the same time, thereby increasing the audience's understanding and retention level. With pictures, the concepts or ideas you present are no longer simply words - but words plus images.

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.