How living things move carbon

Grade 9 Science Worksheet

Circle the best answer.

1. 1.

   “model, not to scale” Bo follows a carbon atom from the air into the grass and back to the air. Which two processes move it along arrows 1 and 2?

   • Cellular respiration, then photosynthesis
   • Photosynthesis, then decomposition
   • Photosynthesis, then photosynthesis again, since the atom stays in the grass
   • Photosynthesis, then cellular respiration
2. 2.

   Esme follows the carbon atoms in a fallen leaf as decomposers break it down. Which statement fits the diagram?

   • The atoms pass to the ocean, since decomposers work in the water
   • The atoms vanish from the cycle, since decomposers use up carbon atoms
   • The atoms move on, as carbon dioxide in the air or as carbon in the soil
   • New atoms form in the leaf, so its carbon is replaced by new carbon
3. 3.

   Jun reads a model budget for the air above a meadow. The carbon in the air stays the same all year. How much does photosynthesis take out?

   • 5 units
   • 35 units
   • 55 units
   • 60 units
4. 4.

   Kira reads a model budget for the air with the ocean included. The carbon in the air stays the same this year. How much does photosynthesis take out?

   • 85 units
   • 80 units
   • 65 units
   • 100 units
5. 5.

   The carbon stored in the plants stays the same this year. Luz reads a model budget for the carbon stored in a meadow’s plants. The plants’ store stays the same this year. How much passes to the grasshoppers?

   • 20 units
   • 55 units
   • 45 units
   • 140 units
7. 6.

   Milo reads a model graph of the carbon dioxide in the air above a northern forest through one year. In which month is it lowest?

   • May
   • March
   • December
   • August
8. 7.

   Noah sees the carbon dioxide level fall from April to August on the graph. Which explanation fits?

   Use the picture in question 6.

   • The ocean stops exchanging carbon dioxide with the air during the summer
   • Growing plants take in more carbon dioxide by photosynthesis than respiration returns
   • Growing plants stop respiring, so less carbon dioxide returns to the air
   • Growing plants release more carbon dioxide by photosynthesis than they take in
9. 8.

   Pia uses the same graph to compare April with August. What happened to the carbon dioxide, and why?

   Use the picture in question 6.

   • A fall of 8 ppm, as growing plants took in carbon dioxide
   • A rise of 8 ppm, as growing plants gave off carbon dioxide
   • A fall of 8 ppm, as the plants stopped respiring in summer
   • A fall of 6 ppm, as growing plants took in carbon dioxide

10. Read this first

    Use the table

    Card (real data, NASA Earth Observatory, 2011). Carbon stored and moved.

    store or cycle	carbon amount
    stored in rocks	about 65,500 billion metric tons
    slow carbon cycle	10–100 million metric tons a year
    fast carbon cycle	1,000–100,000 million metric tons a year

11. 9.

    Tala wants the rock store in million metric tons, the same unit as the yearly flows. How many million metric tons is 65,500 billion metric tons?

    • 6,550,000 million metric tons
    • 65,500,000 million metric tons
    • 65,500 million metric tons
    • 655,000 million metric tons
12. 10.

    Zee reads that plants and phytoplankton are the main parts of the fast carbon cycle. Which statement about the fast cycle fits the card and that fact?

    • It leaves out the ocean, since just land plants take part in it
    • It makes new carbon in plants, so the carbon total grows each year
    • It moves carbon through living things such as plants and phytoplankton
    • It moves carbon through rock layers over millions of years