How carbon moves through living things and the air

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Table (NOAA Global Monitoring Laboratory, Mauna Loa, Hawaii), columns year, carbon dioxide in the air (ppm, yearly average)

   1960, 317; 1980, 339; 2000, 370; 2020, 414; 2024, 425.

2. 1.

   By how much did carbon dioxide in the air rise from 1960 to 2020, Ari?

   • About 60 ppm
   • About 97 ppm
   • About 414 ppm
   • About 317 ppm
3. 2.

   By how much did carbon dioxide in the air rise from 2000 to 2024, Bo?

   • About 55 ppm
   • About 370 ppm
   • About 425 ppm
   • About 24 ppm
4. 3.

   NOAA measures carbon dioxide rising year after year. What does NOAA say is the main cause, Jun?

   • Decomposers breaking down more leaves
   • Plants taking in less each year
   • More volcanoes erupting
   • People burning fossil fuels for energy
5. 4.

   Plants and the ocean take in carbon dioxide too. Why does the air's carbon dioxide still rise, Kira?

   • They remove just about half of what fuels add
   • Burning destroys the carbon instead
   • The ocean adds the extra
   • They make more carbon dioxide
6. 5.

   Coal and oil formed from plants buried long ago. When they burn, where does their carbon go, Luz?

   • Nowhere: burning destroys it
   • Into the air as carbon dioxide
   • It turns into energy and is gone
   • Back into living plants at once
7. 6.

   A carbon atom goes from the air into a leaf, the leaf falls, and fungi break it down. Which processes start and end that loop, Noah?

   • Decay, then photosynthesis
   • Photosynthesis, then decay
   • Burning, then dissolving
   • Respiration, then photosynthesis
8. 7.

   Ancient plants took in carbon dioxide and were buried and became coal. Today the coal is burned. Which two processes start and end that path, Pia?

   • Dissolving, then decay
   • Respiration, then decay
   • Burning, then photosynthesis
   • Photosynthesis, then burning
9. 8.

   Ren says plants make their carbon out of sunlight. Agree or disagree?

   • Agree: sunlight turns into carbon
   • Disagree: it comes from the soil
   • Agree: plants need no air
   • Disagree: the carbon comes from carbon dioxide
10. 9.

    Tala says burning fossil fuels gets rid of their carbon. Agree or disagree?

    • Agree: burning destroys carbon
    • Disagree: it moves into the air
    • Agree: the carbon becomes energy
    • Disagree: it stays in the fuel
11. 10.

    Zee says volcanoes cause most of the rise in carbon dioxide. Agree or disagree?

    • Agree: plants add the most
    • Agree: volcanoes add the most
    • Disagree: the ocean adds the most
    • Disagree: people emit far more than volcanoes