Sustainability & Solutions — Drills · Grade 12 Science

Chapter: Conservation, Systems & Environmental Design

What these drills covers

By the end of Sustainability & Solutions you should be able to:

6 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: sustainability, ecological footprint, biocapacity, renewable energy, carrying capacity.

Problem 1

In the waste hierarchy 'reduce, reuse, recycle,' which action generally has the biggest positive impact?
  1. Recycling the item after use
  2. Reusing the item several times
  3. Reducing how much you use in the first place
  4. Sending the item to a landfill
Answer and explanation

Reducing how much you use in the first place

Reducing consumption prevents the resource use, energy, and waste up front, which is why it comes first and matters most; recycling still requires collecting and reprocessing materials.

Problem 2

Which of these is NOT a renewable energy source?
  1. Solar
  2. Wind
  3. Geothermal
  4. Coal
Answer and explanation

Coal

Coal is a finite fossil fuel that releases carbon when burned; sunlight, wind, and geothermal heat are continuously replenished by nature.

Problem 3

A country's average ecological footprint is 3.2 global hectares per person, while Earth can sustainably provide about 1.6 global hectares per person. If everyone lived this way, how many Earths would humanity need?
Answer and explanation

2 Earths

Earths needed = footprint ÷ biocapacity = 3.2 ÷ 1.6 = 2.0 Earths.

Problem 4

In a hypothetical footprint accounting model, The ecological footprint of humanity is often stated as about '1.7 Earths.' Explain what that figure means.
Answer and explanation

It means humanity currently uses renewable resources and produces waste about 1.7 times faster than the planet can regenerate resources and absorb that waste in a year. Since there is only one Earth, we are overshooting its biocapacity by about 70%, drawing down natural capital — like forests, fisheries, and a stable atmosphere — instead of living within what nature renews each year.

Problem 5

What was the outcome of the Montreal Protocol?
  1. Nations phased out ozone-destroying chemicals, and the ozone layer is now healing
  2. Global temperatures immediately stopped rising
  3. All plastic production was banned worldwide
  4. Fossil fuels were completely eliminated
Answer and explanation

Nations phased out ozone-destroying chemicals, and the ozone layer is now healing

By coordinating a global phase-out of CFCs, the Montreal Protocol allowed the ozone layer to begin recovering — a landmark example of successful international environmental policy.

Problem 6

Explain why systemic or policy-level changes often have more leverage to protect the environment than individual actions alone.
Answer and explanation

The largest environmental impacts come from how whole societies produce energy, transport people and goods, and grow food — systems shaped by laws, markets, and infrastructure rather than by any one person. Policy-level changes, like switching a national grid to renewables or regulating a pollutant, alter those systems for everyone at once, cutting impacts at their source. Individual actions matter and build support, but they cannot match the scale of change that system-level decisions deliver.

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