Biogeochemical Cycles and Ecosystems

A farmer notices that after planting nitrogen-fixing plants, the soil quality improves. The part of the nitrogen cycle responsible for this is (a)   .

• Denitrification
• Nitrification
• Nitrogen fixation
• Ammonification

A scientist studying a lake finds that excess fertilizers have caused an overgrowth of algae, leading to fish deaths. The biogeochemical cycle most involved is (a)   .

• Carbon cycle
• Nitrogen cycle
• Phosphorus cycle
• Water cycle

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NGSS.MS-LS2-1

NGSS.MS-LS2-3

NGSS.MS-LS2-4

During the carbon cycle, which process removes carbon dioxide from the atmosphere?

• Respiration

• Decomposition

• Photosynthesis

• Combustion

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NGSS.MS-LS1-6

A scientist measures an increase in atmospheric carbon dioxide. Which of the following is NOT a likely cause?

• Burning fossil fuels

• Deforestation

• Increased photosynthesis

• Volcanic activity

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NGSS.MS-LS1-6

A pond ecosystem includes frogs, fish, insects, plants, and bacteria. Which of these is a biotic factor?

• Water

• Rocks

• Bacteria

• Sunlight

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NGSS.MS-LS2-2

Which factor is an abiotic component of a desert ecosystem?

• Cacti

• Lizards

• Temperature

• Insects

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NGSS.MS-LS2-3

Which of the following best describes an ecosystem?

• A group of the same species living in one area

• A community of organisms interacting with their environment

• A group of organisms of different species in a region

• The physical environment of a specific species

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NGSS.MS-LS2-3

A food chain in a forest includes: grass → grasshopper → frog → snake → hawk. What is the role of the frog?

• Primary producer

• Primary consumer

• Secondary consumer

• Tertiary consumer

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NGSS.MS-LS2-3

Which organism in a food web is most affected by biomagnification?

• Grass

• Rabbit

• Snake

• Hawk

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NGSS.MS-LS2-4

A sudden decrease in the population of primary producers in an ecosystem would most likely result in (a)   .

• An increase in herbivores
• A decrease in primary consumers
• A decrease in decomposers
• No effect on the ecosystem

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NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-3

NGSS.MS-LS2-4