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AP Environmental Science Hard practice

15 questions

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Hard practice

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Question 1

Methane (CH₄) contributes to global warming despite being present at far lower atmospheric concentrations than CO₂. The reason methane is such a significant greenhouse gas concern is that:

A.Methane lasts longer in the atmosphere than CO₂ (thousands of years vs. ~12 years)B.Methane's global warming potential (GWP) is ~80× that of CO₂ over a 20-year timeframe, so even small mass emissions cause significant warmingC.Methane blocks more ultraviolet radiation than CO₂, protecting stratospheric ozoneD.Methane is heavier than air and accumulates at ground level, trapping heat more efficiently near the surface

Question 2

A population of 500 deer occupies a 50 km² forest. Biologists find 40 births and 20 deaths in one year, with 5 deer immigrating and 10 emigrating. What is the net change in the population over the year?

A.ΔN = +15B.ΔN = +20C.ΔN = +25D.ΔN = −15

Question 3

A food chain shows: phytoplankton → zooplankton → small fish → tuna. If phytoplankton store 100,000 kcal of energy, approximately how many kcal are available at the tuna level (assuming 10% efficiency at each step)?

A.1,000 kcalB.100 kcalC.10 kcalD.10,000 kcal

Question 4

Which conservation strategy is most likely to protect the greatest number of species across a landscape?

A.Captive breeding programs for individually endangered speciesB.Protecting large, contiguous core reserves connected by habitat corridorsC.Focusing protection on charismatic megafauna as umbrella speciesD.Banning all human activities across a small, intensively managed reserve

Question 5

A farmer applies excess nitrogen and phosphorus fertilizer to fields near a lake. After a heavy rain, runoff enters the lake. Over the following weeks, which sequence of events is most likely to occur?

A.Algae die → bacteria decompose algae → oxygen levels rise → fish thriveB.Algal bloom → algae die → bacterial decomposition → oxygen depletion (hypoxia) → fish killsC.Nitrogen directly toxifies fish before algae can growD.Phosphorus precipitates out immediately, preventing algal growth

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Question 6

Wolves were reintroduced to a habitat with an existing deer population of 800. The area's carrying capacity for deer is 600. Based on logistic growth principles, what should happen to the deer population over the next few years even WITHOUT wolves?

A.Deer population grows because there are many individuals to reproduce.B.Deer population declines toward 600 due to density-dependent resource limitation.C.Deer population remains stable at 800 because it has already reached equilibrium.D.Deer population crashes to zero because the habitat is degraded past recovery.

Question 7

The Exxon Valdez oil spill (1989) and Deepwater Horizon spill (2010) differed in that Deepwater Horizon released oil:

A.From a surface tanker, making containment and skimming easier than a deepwater blowoutB.From a subsurface wellhead (~1,500 m below sea surface), making containment far more difficult than a surface spillC.In an arctic environment where cold temperatures accelerated biodegradationD.Only refined petroleum products, which are less toxic to wildlife than crude oil

Question 8

According to the species-area relationship, if an island's area is reduced by 90%, approximately what fraction of its species are expected to survive?

A.90% of species surviveB.~50% of species surviveC.~10% of species surviveD.All species survive because they adapt to smaller habitat

Question 9

Deforestation of a watershed causes increased sediment runoff into a nearby river. Which biogeochemical cycle is MOST directly disrupted by the loss of plant root systems holding the soil?

A.Carbon cycle — increased CO₂ from decomposing rootsB.Nitrogen cycle — excess nitrogen gas lost to atmosphereC.Phosphorus cycle — phosphorus-laden sediment leaches into the riverD.Water cycle — reduced transpiration only

Question 10

A population of 200 squirrels lives in a woodland. Ecologists estimate the carrying capacity of that woodland at 400 squirrels. Using logistic growth, at what population size would the growth rate be at its maximum?

A.At N = 400 (at carrying capacity)B.At N = 200 (at K/2)C.At N = 1 (at the very start of growth)D.At N = 600 (above K)

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Question 11

La Niña conditions are characterized by which oceanic and atmospheric pattern in the Pacific?

A.Weakened trade winds and eastward shift of warm surface waterB.Stronger-than-normal trade winds, cooler central/eastern Pacific, enhanced upwelling off South AmericaC.Reversal of the thermohaline circulation and shutdown of the Gulf StreamD.Warmer-than-normal Indian Ocean temperatures replacing cold Pacific anomalies

Question 12

Stratospheric ozone is depleted by chlorofluorocarbons (CFCs). Which chemical process explains how a single CFC molecule can destroy thousands of ozone molecules?

A.CFCs directly absorb UV radiation and radiate it harmlessly as infrared, blocking ozone formation.B.UV radiation breaks CFCs, releasing Cl atoms that catalytically destroy ozone in a chain reaction.C.CFCs react with oxygen to form chlorine dioxide, which blocks ozone from absorbing UV.D.CFCs increase tropospheric ozone, which diffuses upward and replaces stratospheric ozone with a different molecule.

Question 13

Under the U.S. Clean Air Act's cap-and-trade (emissions trading) system for sulfur dioxide, power plants that reduce SO₂ emissions below their cap can:

A.Receive a tax exemption from all future federal environmental regulations.B.Sell their unused emission allowances to other plants that need them, creating economic incentive for reduction.C.Increase their emissions cap in future years as a reward for current reductions.D.Apply excess reductions to offset CO₂ emissions under a separate carbon trading scheme.

Question 14

Natural gas emits approximately half the CO₂ of coal per unit of energy produced. However, natural gas has a significant climate disadvantage compared to coal because:

A.Burning natural gas releases sulfur dioxide, which is a more potent greenhouse gas than CO₂.B.Methane (the primary component of natural gas) that leaks before combustion is a potent short-term greenhouse gas.C.Natural gas infrastructure is more expensive, meaning more forests are cleared to fund it.D.Natural gas combustion produces nitrogen oxide, which breaks down the ozone layer.

Question 15

Biomass energy (e.g., burning wood, crop residues, or biofuels) is sometimes considered 'carbon neutral.' This claim assumes that:

A.Burning biomass releases no CO₂ because the carbon is in organic form.B.The CO₂ released by combustion was recently absorbed from the atmosphere by growing plants, and new plants will reabsorb it.C.Biomass releases less CO₂ per unit energy than natural gas, making it inherently cleaner.D.Carbon capture technology removes all CO₂ from biomass combustion flue gases.

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