An investigative essay discusses urban agroecology initiatives in Mexico City:
"Amid the sprawling concrete expanse of Mexico City, the ancient lacustrine network of Xochimilco is experiencing a modern ecological renaissance. Agronomists and local chinamperos are revitalizing the pre-Columbian system of chinampas—artificial agricultural islands built on shallow lake beds—to address contemporary metropolitan vulnerabilities. While skeptics initially viewed the technique as a picturesque relic of indigenous history, recent field evaluations demonstrate its extraordinary multifunctionality. The layered willow-root and sediment architecture naturally filters heavy metals and excess nitrates from urban runoff, while creating microclimatic cooling zones that mitigate the capital's severe urban heat island effect. Furthermore, these bio-diverse plots yield high-density organic produce with zero chemical inputs, supplying metropolitan food cooperatives at a fraction of the carbon footprint of industrial transport. Rather than merely preserving an ancestral heritage, this revived wetland agriculture serves as a viable, decentralized ecological infrastructure that simultaneously enhances urban climate resilience and local food sovereignty."
Which of the following best expresses the main idea of the passage?
- AThe willow-root and sediment architecture of artificial islands functions primarily to filter nitrates and industrial heavy metals from contaminated runoff.
- BThe modern adoption of pre-Columbian agricultural techniques is primarily an aesthetic endeavor designed to boost cultural tourism in historical canals.
- The restoration of traditional chinampa wetland agriculture provides an effective decentralized framework for urban climate adaptation and sustainable food security.Answer
- DReviving ancient lacustrine farming has fully replaced industrial food distribution networks across the entire metropolitan area.