Food Security: What Limits Yield and What It Costs to Raise It · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

More food from the same field

Science · Organisms & Life Processes · ages 15-16
Name ______________________   Date ____________

  1. About how much of the energy in food becomes new body at the next level?

    • Almost all of it
    • About half of it
    • About a tenth of it

  2. What does food security mean?

    • A country grows a very large harvest
    • Everyone has reliable access to enough safe food
    • Food prices stay low all year

  3. Fertilisers boost crop growth but can leak into rivers.

    Circle one:   True   False

  4. Which threats to food supply are spreading as the climate changes?

    • Pests, diseases and extreme weather
    • Floods only, in coastal cities
    • Soil loss only, in deserts

  5. A field holds 1000 units of food energy in grain. Cattle eat it all and keep about a tenth. About how much reaches people as meat?

    • 900 units
    • 500 units
    • 100 units

  6. A field stores 2000 units of food energy in grain. Animals eat it all and pass on a tenth. About how many units reach people?

    Answer: ______________

  7. A farmer says pesticides have no costs since the pests die. What is the flaw?

    • Pesticides cost nothing to spray
    • Pests breed resistance while wildlife and water suffer
    • Pesticides work better every single year

  8. Why does eating less meat free up more food than you might expect?

    • Each skipped animal level saves the 90 percent that level would burn
    • Meat holds no energy worth counting
    • Plants grow faster whenever meat is refused
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Answer key

For grown-ups. Fold this page away before handing over the rest.

More food from the same field W1-mt_SprRvGuyrK-s1

  1. About a tenth of it · Each level keeps roughly a tenth, while the rest leaks away as heat, movement and waste.
  2. Everyone has reliable access to enough safe food · Security is about reliable access to safe food, not the size of the harvest.
  3. True · That leak is the price side of the fertiliser deal.
  4. Pests, diseases and extreme weather · Climate change spreads pests and diseases and sharpens storms and drought.
  5. 100 units · A tenth of 1000 is 100, since the cattle burn the other 900 staying alive.
  6. 200 · A tenth of 2000 is 200 units reaching people as animal food.
  7. Pests breed resistance while wildlife and water suffer · Dead pests today still leave resistance, pollution and harmed wildlife behind.
  8. Each skipped animal level saves the 90 percent that level would burn · Skipping a level keeps the nine tenths that level would have burned alive.
Worksheet · LightMySky