AP Environmental Science 4.6: Watersheds
Practice AP Environmental Science questions on watershed boundaries, area, slope, soil, vegetation, land use, hypotheses, and controls.
- Syllabus
- Effective Fall 2025
- Course
- AP Environmental Science
Practice AP Environmental Science questions on watershed boundaries, area, slope, soil, vegetation, land use, hypotheses, and controls.
The dead zone in the Gulf of Mexico occurs every summer when winter snow melts and spring rain flows into the Mississippi River. Recent studies have shown that both the total area covered by algae and the depth of the algal mass in the dead zone are increasing.

Various land use practices can have different effects on the waters that surround a dead zone.
Identify the land use that covers the least amount of area in the Mississippi River watershed, based on the diagram.
- Urban
Researchers want to examine the effect of riparian vegetation buffers on water quality in streams in agricultural areas. Researchers will measure the water nutrient concentrations over the course of one year. The study sites are located 100 meters downstream from areas either with or without riparian vegetation buffers.
Identify a testable hypothesis for the study.
Identify a testable hypothesis for the study.
1 point
Accept one of the following:
- If riparian buffers are present in agricultural areas, then the level of nitrates/phosphates/nutrients downstream will be lower than areas without riparian buffers.
- If riparian buffers are present in agricultural areas, then the level of nitrates/phosphates/nutrients downstream will be higher than areas without riparian buffers.
- If riparian buffers are present in agricultural areas, then the level of nitrates/phosphates/nutrients downstream will remain the same in areas with and without riparian buffers.
Describe a control that the researchers could use in the study.
Describe a control that the researchers could use in the study.
1 point
- Stream sites that are 100 meters downstream from areas without riparian buffer zones