Q.1
What process takes carbon dioxide from the air and makes it available to land living animals?
  • Photosynthesis
  • Respiration
  • Lightning strikes
  • Burning fossil fuels
Q.2
Which two natural processes return carbon dioxide to the air?
  • Photosynthesis and respiration
  • Respiration and decomposition
  • Digestion and eating
  • Using nuclear fuels
Q.3
Which human activity returns carbon dioxide to the air?
  • Generating electricity
  • Driving cars
  • Flying planes
  • All of the above
Q.4
Why do fossil fuels have a high carbon content?
  • They are made in swamps
  • They are made from organisms that were once alive
  • They are made from limestone
  • They were made in fires started by lightning millions of years ago
Q.5
Which of the following is a problem caused by humans burning fossil fuels?
  • A hole in the ozone layer
  • Deforestation
  • Global warming
  • All of the above
Q.6
How might burning fossil fuels be creating global warming?
  • Because fossil fuels will be all used up in a few decades
  • Because burning fossil fuels is a very dangerous process
  • Because fossil fuels are not compatible with the new biofuels
  • Because burning fossil fuels adds CO2 to the atmosphere faster than it can be removed
Q.7
How is carbon in plants passed on to the rest of the cycle?
  • Only death and decay
  • Only by being eaten
  • Through food webs
  • By forming coal
Q.8
Carbonate rocks lock carbon out of the cycle for millions of years. Which of the following does put CO from these rocks back into the current carbon cycle?
  • Grinding them up into small particles to use for making roads
  • Manufacturing cement
  • Heat from volcanoes
  • When they are subducted during plate tectonics
Q.9
Why do waste materials and dead plants or animals decay?
  • They are broken down by microorganisms
  • They get rained on
  • They slowly sink into the ground
  • Sunlight breaks down their chemicals
Q.10
How is the CO from the air introduced into a food web?
  • Plants breathe it in and when an animal eats the plant, it eats the CO2 as well
  • It forms carbonate rocks that eventually come to the surface
  • Plants use the products of photosynthesis to manufacture carbohydrates, fats and proteins
  • Bacteria living in nodules on the root convert it into plant food
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