Where is the longest-surviving ancient roman bridge?

Puente Romano at Mérida, Spain (today 790 m)

Merida

Explanation:

how many characteristics are used to describe living things?

explanation:

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.