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

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

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

   • 55 units
   • 60 units
   • 5 units
   • 35 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?

   • 80 units
   • 85 units
   • 100 units
   • 65 units
6. 5.

   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
   • August
   • March
   • December
7. 6.

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

   Use the picture in question 5.

   • Growing plants release more carbon dioxide by photosynthesis than they take in
   • Growing plants stop respiring, so less carbon dioxide returns to the air
   • The ocean stops exchanging carbon dioxide with the air during the summer
   • Growing plants take in more carbon dioxide by photosynthesis than respiration returns
8. 7.

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

   Use the picture in question 5.

   • 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

9. 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

10. 8.

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

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

    • 655,000 million metric tons
    • 65,500,000 million metric tons
    • 6,550,000 million metric tons
    • 65,500 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 moves carbon through rock layers over millions of years
    • 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