Final answer:
The negative impact of using hydroelectric power is the destruction of natural habitats, as building a reservoir for a hydroelectric plant can flood large areas, disrupt aquatic and terrestrial ecosystems, and displace indigenous populations.
Step-by-step explanation:
The negative impact of using hydroelectric power is described in option B, which states: 'Building a reservoir to hold water for a hydroelectric plant can destroy natural habitats.' This is because the creation of reservoirs often leads to the inundation of large land areas, which can affect terrestrial and aquatic ecosystems. The construction of dams in rivers for hydroelectricity can affect fish migrations, such as salmon in the Columbia River, change water temperatures, water chemistry, and alter flow characteristics. This can lead to significant ecological disruptions both upstream and downstream.
Additionally, hydroelectric facilities can also lead to issues such as increased water acidity due to decomposing plant material, erosion to the turbines leading to shorter lifespans, and the potential displacement of indigenous populations whose lands may be flooded. Despite the clean energy produced, these environmental impacts highlight a major downside to hydroelectric power.