How living things move carbon

Grade 9 Science Worksheet

Circle the best answer.

1. 1.

   Ari follows one carbon atom along arrows 1 to 4. It starts in the air and ends back in the air. In what form does it return, and who releases it?

   • Carbon dioxide gas, released by photosynthesis
   • Carbon dioxide gas, released by decomposers
   • New carbon atoms, made by decomposers
   • No gas, since decomposers destroy the carbon
2. 2.

   “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?

   • Photosynthesis, then photosynthesis again, since the atom stays in the grass
   • Photosynthesis, then decomposition
   • Photosynthesis, then cellular respiration
   • Cellular respiration, then photosynthesis
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
   • 55 units
   • 35 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
   • 100 units
   • 65 units
   • 80 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?

   • December
   • August
   • March
   • May
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 stop respiring, so less carbon dioxide returns to the air
   • Growing plants release more carbon dioxide by photosynthesis than they take in
   • Growing plants take in more carbon dioxide by photosynthesis than respiration returns
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 6 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 growing plants took in carbon dioxide
   • A fall of 8 ppm, as the plants stopped respiring in summer

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.

    Ren reads real NASA data on how much carbon moves in each cycle every year. Which statement follows from the card?

    • The fast cycle adds new carbon to Earth each year, so it moves more
    • The slow cycle moves more carbon each year, since rocks hold the most carbon
    • The two cycles move about the same amount of carbon each year
    • The fast cycle moves at least 10 times as much carbon as the slow cycle
12. 10.

    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?

    • 65,500,000 million metric tons
    • 65,500 million metric tons
    • 655,000 million metric tons
    • 6,550,000 million metric tons