Question

Read the passage below carefully:

For centuries, the ancient city of Kano in northern Nigeria has maintained a renowned leather tanning industry, utilizing traditional vegetable-tanning techniques derived from native plants such as the pods of the Acacia nilotica tree. Unlike modern industrial tanning methods that rely heavily on synthetic chromium salts—which generate toxic chemical effluents that contaminate surrounding soils and river systems—the indigenous Kano process is largely biodegradable and environmentally sustainable. However, despite these ecological advantages, the traditional leather sector faces mounting threats from rapid urbanization, shrinking supplies of raw hides, and unregulated cheap synthetic leather imports. Furthermore, while local tanners possess deep craft knowledge, the lack of modern wastewater treatment facilities in informal tanning clusters still leads to localized organic pollution. Consequently, environmental scientists argue that rather than replacing traditional tanning with industrial chemical processes, developmental policies should focus on modernizing waste management infrastructure while preserving the eco-friendly organic tanning formulations that have sustained the region's craft heritage for generations.

Match each excerpt or statement from the passage on the left to its correct functional role in the author's argument on the right.