Resources & Human Decisions — Chapter quiz · Earth & Space Science, Grade 9

Evaluate resource use and environmental solutions with quantitative evidence and trade-offs.

Problem 1

Which of these is a nonrenewable resource?
  1. Wind
  2. Sunlight
  3. Natural gas
  4. Flowing river water
Answer and explanation

Natural gas

Natural gas is a fossil fuel that takes millions of years to form, so it's nonrenewable.

Problem 2

Why are coal, oil, and natural gas NOT distributed evenly around the world?
  1. Their locations depend on specific geologic processes that occurred in the past
  2. Every country has exactly the same amount hidden at different depths
  3. Wind currents move them underground every year
  4. Governments decide randomly where to place them
Answer and explanation

Their locations depend on specific geologic processes that occurred in the past

Where these resources formed depends on the specific geologic history of that location.

Problem 3

A city's population doubles while per-capita resource use stays unchanged. By what factor does total resource demand increase?
Answer and explanation

2 ×

The population factor alone is 2, and per-capita use didn't change, so total demand doubles.

Problem 4

Which statement best describes the goal of sustainability?
  1. Using as many resources as possible right now, regardless of the future
  2. Meeting today's needs without ruining the ability of future generations to meet their own needs
  3. Avoiding the use of any natural resources at all
  4. Relying only on nonrenewable resources for stability
Answer and explanation

Meeting today's needs without ruining the ability of future generations to meet their own needs

Sustainability means balancing present needs with the ability of future generations to meet their own.

Problem 5

Which pairing is correct?
  1. Groundwater — always renewable regardless of use
  2. Solar — nonrenewable
  3. Fossil fuel — nonrenewable on human timescales
  4. Wind — nonrenewable
Answer and explanation

Fossil fuel — nonrenewable on human timescales

Fossil fuels form far too slowly to be replaced as they are used.

Problem 6

Explain what information you would need to judge whether a fishery is being used sustainably.
Answer and explanation

The size of the stock and how it is changing, the rate at which the population reproduces and grows, and the quantity caught each year including what is taken unreported. Comparing catch with growth shows whether the stock is being drawn down. Several years of data are needed, since natural variation can make one good or bad year look like a trend.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 7

Independent chapter check: A locally renewable store starts at 200 units, gains 12 units/year and loses 17/year for six years. Find final stock. Explain why the renewable label and a per-use efficiency improvement alone do not guarantee preservation of the store.
Answer and explanation

Net change is −5 units/year, giving −30 over six years and final stock 170. Renewal can be exceeded, and total use depends on quantity of service as well as efficiency; check actual replenishment and withdrawal conditions.

Net change is −5 units/year, giving −30 over six years and final stock 170. Renewal can be exceeded, and total use depends on quantity of service as well as efficiency; check actual replenishment and withdrawal conditions.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 8

The strongest evidence that a restoration project succeeded would be
  1. positive public opinion
  2. a measured recovery against a baseline and an untreated comparison site
  3. the project's cost
  4. the number of volunteers
Answer and explanation

a measured recovery against a baseline and an untreated comparison site

Only measurement against a baseline and a control separates the project's effect from background change.

Problem 9

Explain why reducing a single pollutant may not restore an ecosystem.
Answer and explanation

Ecosystems are usually under several pressures at once — habitat loss, invasive species, altered water flow, climate change — and removing one leaves the others acting. A system may also have shifted to a different state that persists after the original pressure is reduced, as a lake can stay turbid after nutrient inputs fall. Recovery therefore needs the full set of pressures addressed and time, and in some cases active intervention rather than removal alone.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 10

Independent chapter check: Population rises 20% while average use/person falls 10%. Calculate the total-demand factor and explain one limit of using the average to describe impacts on all families.
Answer and explanation

1.20×0.90 = 1.08, an 8% total rise. A population average hides differences in use, access and circumstances; it does not establish identical individual consumption or responsibility.

Convert changes to factors 1.20 and 0.90.

Multiply to get 1.08, an 8% rise.

Identify the aggregation limit and ask for group-specific evidence when relevant.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 11

Runoff falls from 150 to 120 units. Find percent reduction.
Answer and explanation

20 %

30 ÷ 150 × 100 = 20.

Problem 12

One design has the lowest operating energy. Why might that not settle the choice?
Answer and explanation

Cost, reliability, maintenance, manufacturing impacts, accessibility, and other criteria or constraints may differ.

Problem 13

Independent chapter check: A matched storm baseline gives 120 m³ runoff. Design A gives 72 m³ at cost 85; B gives 54 m³ at cost 110. Budget limit is 100. Calculate both reductions, identify feasibility and state a further test before recommending A.
Answer and explanation

A reduces runoff by 40% and meets the cost constraint. B reduces it by 55% but exceeds the budget. Test repeated relevant storm/soil conditions, maintenance and effects elsewhere, checking all success criteria before recommending A.

A: (120−72)/120 = 0.40 = 40%.

B: (120−54)/120 = 0.55 = 55%, but cost 110 exceeds 100.

Evaluate repeated performance, life-cycle effects and maintenance within the defined service.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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