Which aspect of Islam unite Muslims throughout the Islamic world

The movements that emerged within Islam were a split between Sunni & Shiites. Also there was a linking between Europe, Asia and Africa due to trade. Another movement that emerged was that Arabic became the shared language of Muslims. Muslims learned Arabic because it is the language of the Quran. (Wherever Islam spread, so did knowledge of Arabic.)

Explanation:

how do you know that

explanation:

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.