Final answer:
Concerns about the Line 5 oil pipeline stem from its risk to the Great Lakes due to potential oil spills from its aging structure, similar to protests against the Keystone XL Pipeline for its environmental risks.
Step-by-step explanation:
People are concerned about the Line 5 oil pipeline in Michigan for environmental reasons. Specifically, the potential for an oil spill in the Straits of Mackinac poses a significant threat. The pipeline is aging, and its location creates a risk for the Great Lakes' ecosystem, which is a critical freshwater resource. Concerns are akin to those raised regarding the Keystone XL Pipeline, where citizens protested due to the risks it posed to water sources and natural habitats.
The protest against Line 5 is part of a broader environmental debate where the necessity for energy and economic growth is weighed against the need to protect the environment. Construction and potential leaks or ruptures of pipelines can threaten water sources, disrupt animal migration, and harm indigenous species.