Soru

Read the passage below carefully:

For centuries, earthen building techniques across the West African Sahel have relied on sun-dried mud bricks and thick rammed-earth walls to mitigate extreme daily temperature fluctuations. Recent microclimate studies in historic settlements confirm that the high thermal mass of cob structures absorbs solar radiation during peak daylight hours and gradually releases stored heat overnight, significantly reducing internal ambient temperatures without mechanical cooling. Consequently, urban planners advocating for sustainable African architecture argue that traditional earth construction offers a crucial, carbon-neutral blueprint for modern climate adaptation in rapidly expanding tropical cities. However, widespread adoption remains constrained by socio-cultural stigmas that falsely equate earthen housing with rural poverty, alongside a prevalent regulatory bias toward imported Portland cement. Furthermore, the vulnerability of untreated earth surfaces to seasonal torrential rainfall requires periodic structural maintenance, which deters real-estate developers focused on immediate low-maintenance yields. Re-engineering raw earth with non-toxic bio-binders presents a promising path to overcome these durability challenges while preserving traditional thermal advantages.

Based on the passage above, match each statement from the text with its corresponding discourse role in the passage's argument structure.