Final answer:
Urbanization affects South America's environment primarily through deforestation and the alteration of the hydrologic cycle, with the former having global and the latter having local impacts.
Step-by-step explanation:
Urbanization in South America significantly impacts the environment in multiple ways. One of the most critical effects is the deforestation that occurs to make way for expanding cities and infrastructure. This deforestation leads to a decrease in biodiversity, habitat loss, and contributes to climate change. Another crucial consequence is the alteration of the hydrologic cycle, due to the increase in impermeable surfaces such as roads and buildings, which reduces the ground's ability to absorb water, leading to increased runoff and potential flooding. I chose this order because deforestation has both immediate and long-term global consequences, while the alteration of the hydrologic cycle has more direct, localized effects, but both are integral in considering the environmental health of urban areas.