Final answer:
Peace was the key attribute that allowed for trade to thrive in the three Muslim empires by ensuring safe trade routes, common legal and cultural frameworks due to the spread of Islam, and the prosperity of cities and kingdoms through the active exchange of goods and technology.
Step-by-step explanation:
The attribute that allowed for trade to thrive in all three Muslim empires was peace. In the context of the Islamic world, peace was significant because it facilitated the safe passage of goods and traders across vast trade networks. Muslim traders connected regions by both sea and land, with routes stretching from India and Southeast Asia through the Middle East and into Africa. The Islamic faith provided a foundation of common language, legal systems, and customs, which further enhanced trading activities. It is also documented that trade helped expand the reach of Islam and enabled the transportation of enslaved individuals, further influencing economic and cultural exchanges.