Answer:
b. greater species richness.
Step-by-step explanation:
For any civilization , be it the Roman or Greek civilization, the history of a civilization can be studied through the soil. The impacts and effects of urbanization, human activities , natural disasters have a way of either enriching the soil in a civilization and those of the surrounding settlements or making the soil barren and not fit for agricultural purposes.
After carrying out studies noting down important observations, it was discovered that the soil conditions and plant species between 1 and 500 meters from former Roman settlements, researchers and scientists found that sites closer to settlements had a higher soil pH, a large availability and richness living species and availability of phosphorus in the soil.