A biological hazard refers to a biological substance such as viruses, insects, fungus, etc. that can affect humans or other animals' health negatively. In the case of Kris and James, they are exposed to a biological hazard because stagnant water is commonly used by mosquitos to place eggs, this leads to a lot of mosquitos around stagnant waters and therefore a higher risk of mosquito-transmitted diseases such as malaria. Besides this, stagnant water is highly polluted and includes bacteria and parasites that are harmful.
Building the Canadian hydroelectric plant reduced the rate of erosion after 1906. This change in the rate of erosion is represented by the change in the slope on the graph. Hydroelectric dams convert kinetic energy from moving water to electrical energy.
