Final answer:
Building dams can negatively impact the stability of ecosystems by altering water flows and disrupting species that rely on natural flow patterns, leading to population declines and environmental degradation.
Step-by-step explanation:
Among the human activities listed, building dams to control the flow of water in rivers to produce electricity (option c) can have a negative impact on the stability of a mature ecosystem. Damming rivers changes water flows and can reduce or eliminate native species that are adapted to natural flow patterns. These alterations can lead to declines in populations, especially in species with life cycles that depend on both aquatic and terrestrial habitats.
Furthermore, the disruption of sediment transportation can lead to excessive soil erosion and other negative impacts downstream, which affect the overall health and function of the ecosystem.