Cycles of Matter

The diagram illustrates part of the carbon cycle. Which best describes the diagram?

• A consumer is obtaining carbon by breathing it in from the atmosphere.

• A consumer is obtaining carbon by absorbing it from the soil.

• A consumer is obtaining carbon by eating carbon-based molecules stored in a producer.

• A consumer is obtaining carbon by eating carbon-based molecules stored in a decomposer.

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NGSS.MS-LS2-3

NGSS.MS-LS1-6

Kate wrote the steps of the carbon cycle to describe how carbon is cycled through specific organisms. The steps are in random order. 1 - The rabbit decomposes.

2 - The rabbit eats the carrot plant.

3 - The carrot plant takes in carbon dioxide from the air during photosynthesis.

4 - Carbon compounds are returned to the soil.

• 2, 3, 1, 4

• 3, 2, 1, 4

• 3, 4, 2, 1

• 2, 4, 3, 1

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NGSS.MS-LS2-3

NGSS.MS-LS1-6

Which human activity would most likely decrease the amount of carbon in the atmosphere?

• clearing forests

• heating coal

• burning wood

• planting trees

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NGSS.MS-LS1-6

Which processes result in the release of carbon? Select three options.

• Animals break down food molecules to obtain energy.

• The remains of producers are broken down by decomposers.

• The remains of consumers are broken down by soil decomposers.

• Producers take in carbon dioxide.

• Producers make sugars and starches.

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NGSS.MS-LS2-3

After Gerry mows his lawn, he often puts the grass clippings into his flower garden.

How will this affect his garden?

• It will decrease the amount of carbon in the soil and decrease the amount of carbon dioxide released by decomposers.

• It will increase the amount of carbon in the soil and decrease the amount of carbon dioxide released by decomposers.

• It will decrease the amount of carbon in the soil and increase the amount of carbon dioxide released by decomposers.

• It will increase the amount of carbon in the soil and increase the amount of carbon dioxide released by decomposers.

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NGSS.MS-LS2-3

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Which process occurs when bacteria converts nitrogen gas to a usable form?

• decomposition

• condensation

• fixation

• transpiration

How is the nitrogen cycle important to humans?

• It produces free nitrogen that humans can breathe.

• It converts nitrogen into a form that humans can obtain by eating other organisms.

• It produces nitrogen compounds that humans can breathe.

• It converts nitrogen into a form that humans can obtain by absorbing it through their skin.

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. Which label belongs in the area marked Z?

• take in from atmosphere

• produce themselves

• eat other organisms

• absorb from soil

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NGSS.MS-LS2-3

Cleo has a vegetable garden and wants to increase the amount of nitrogen in the soil.

How can she most likely do this?

• add several soybean plants to her garden

• decrease the amount of fertilizers she uses

• harvest the vegetable plants continuously

• reduce the number of decomposers that live in the soil

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NGSS.MS-LS2-3

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Which best compares the roles of nitrogen-fixing bacteria and certain decomposers in the nitrogen cycle?

• Both organisms convert free nitrogen into nitrogen-containing compounds.

• Both organisms convert nitrogen-containing compounds into free nitrogen.

• The bacteria convert free nitrogen into nitrogen-containing compounds, while the decomposers convert nitrogen-containing compounds into free nitrogen.

• The bacteria convert nitrogen-containing compounds into free nitrogen, while the decomposers convert free nitrogen into nitrogen-containing compounds.