Practice Test 9 - AP Environmental Science

20 questions. Answer them in any order, then submit to see your score and every explanation.

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1. A clearcut removes all trees in a forest patch used by a population of nesting birds that require closed-canopy conditions. What is the most likely immediate ecological impact, and how would selective cutting differ?
2. Which pair of rates most likely indicates Stage 3 of the DTM?
3. In a coastal marsh food chain: cordgrass (Spartina) → grasshopper → marsh frog → heron. Which organism is the secondary consumer?
4. At approximately $35^\circ$S, a weather station reports prevailing surface winds blowing from west to east. Which wind belt is responsible for these prevailing winds?
5. Country J's age-structure diagram has a wide base, but the 0–4 cohort is slightly narrower than 5–9. At the same time, older cohorts taper quickly. What does this most likely indicate?
6. A chemical has an $LD_{50}$ of $0.8\ \text{g/kg}$. Which of the following is the same value expressed in mg/kg?
7. An ecologist compares two prairie sites using a table of species counts. Site A: 8 species total; counts = [50, 50, 50, 50, 50, 50, 50, 50] Site B: 8 species total; counts = [350, 10, 10, 10, 10, 10, 10, 10] Which conclusion is best supported?
8. A tolerance curve for a coastal grass shows survival versus salinity. Survival is highest at 10–20 ppt, reduced at 5–10 ppt and 20–30 ppt, and zero below 5 ppt or above 30 ppt. Which salinity would most likely produce the lowest survival while still being within tolerance limits?
9. A student compares two layers: Layer X contains the ozone layer and warms with altitude; Layer Y is above X and cools with altitude. What is Layer Y?
10. Country G has a nearly rectangular population pyramid, but the 0–4 cohort is slightly narrower than 5–9 and 10–14. Which interpretation is most consistent with this pattern?
11. A lake receives a large influx of phosphorus and nitrogen from a malfunctioning septic system. Which set of observations best matches eutrophication and its consequences?
12. Which pollutant is most associated with incomplete combustion of biomass in poorly controlled systems?
13. In a simplified model, an ozone-monitoring station reports that when total column ozone decreases, measured UV-B at the surface increases. The Antarctic ozone hole is most pronounced in spring due to polar stratospheric clouds (PSCs) that promote reactions converting reservoir chlorine into reactive forms. Which change would most directly contribute to continued recovery of stratospheric ozone under the Montreal Protocol?
14. A country signs the Stockholm Convention after finding PCBs in human breast milk and dioxins in local fish. The goal of the treaty is most directly to:
15. A lake has a steep drop-off near shore. Sunlight reaches the bottom only in a narrow band near the shoreline; beyond that, the bottom is too deep for rooted plants. Which statement best describes how the littoral zone changes compared with a shallow lake?
16. A region's climate normals show that the average number of days above 35°C has increased from 5 days/year (1971–2000) to 18 days/year (1991–2020). Which conclusion best matches climate change impacts on extreme heat?
17. Which stage is best described as "advanced treatment beyond secondary, often including nutrient removal and disinfection to improve effluent quality for sensitive waters"?
18. An open-ocean location is far from land, with surface salinity near 3.5%. Despite abundant sunlight at the surface, measured nitrate and phosphate concentrations are low, and chlorophyll concentrations are low. Which explanation best accounts for the low primary productivity?
19. A subdivision is being built near a stream. The plan includes: (i) wide asphalt roads, (ii) minimal street trees, (iii) a network of vegetated swales (green infrastructure) that route water to a retention pond, and (iv) several rain gardens in cul-de-sacs. Which combination best explains how the swales and rain gardens reduce runoff and improve water quality?
20. A peatland wetland stores large amounts of carbon in waterlogged soils, reducing the amount of $CO_2$ in the atmosphere over long time periods. Which ecosystem service type is this climate-related benefit?

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