Scientists interested in knowing the best way to restore an area after a temporary road was built through it completed a study comparing two treatments: (1) restoring the contour of an area so that there was no longer a depression or cut-through where the road was previously and (2) simply abandoning the area to allow vegetation to return on its own. they wanted to know whether either or both of these treatments would return the aboveground vegetation and the belowground soil properties to their original state, as seen in a similar area where there had never been a road.

This study was focused on the ecosystem level of life's hierarchy. The ecosystem consists of all organisms living in a particular area, as well as the physical components with which the organisms interact, such as air, soil, water, and sunlight. The fact that the researchers were analyzing the above ground vegetation and the below ground soil properties, means that they were focused on the ecosystem.

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.