Free AP Environmental Science Tests
AP Environmental Science FRQ Example 2
After answering AP Environmental Science FRQ 2, you can evaluate this sample response, which would receive a perfect score:
Sample Student Response
(a) One cultural service provided by the dam is recreation, such as boating, fishing, and swimming in the reservoir created behind the dam.
(b) One ecological drawback of the dam is disruption of fish migration. Many fish species, such as salmon, rely on free-flowing rivers to migrate upstream for spawning. The dam blocks their natural migration routes, reducing fish populations and negatively impacting the river ecosystem.
(c) An economic benefit of the dam is hydroelectric power generation, which provides a renewable source of electricity to the city and reduces dependence on fossil fuels, lowering energy costs in the long term.
(d) The dam stores water in a reservoir, and when water is released, it flows through turbines. The kinetic energy of the moving water turns the turbine blades, which are connected to a generator. The mechanical energy of the spinning turbine is then converted into electrical energy by the generator, which is transmitted to the power grid for use in homes and businesses.
(e) Fish ladders — A series of stepped pools that allow salmon to bypass the dam and continue their migration upstream to spawn.
Fish transport systems — Salmon can be physically transported around the dam using trucks or barges to move them upstream to their spawning grounds.
(f) Eutrophication occurs when excess nutrients, such as nitrogen and phosphorus from agricultural runoff, enter a body of water. These nutrients cause rapid growth of algae (algal blooms). When the algae die and decompose, bacteria consume oxygen in the water, leading to hypoxia (low oxygen levels). This lack of oxygen can result in dead zones, where aquatic life cannot survive.
(g) Farmers could implement buffer zones by planting vegetation, such as grass or trees, along the edges of fields and waterways to absorb excess nutrients before they reach the river.
(h) Buffer zones act as a natural filter, absorbing and trapping excess nitrogen and phosphorus from runoff before they enter the river. This reduces nutrient pollution, which in turn limits algal blooms and prevents the oxygen depletion that leads to eutrophication.