The Carbon Cycle

What is the main source of carbon dioxide (CO2) in the atmosphere?

• Volcanic eruptions

• Burning fossil fuels

• Photosynthesis in plants

• Cellular respiration

Answer explanation

Burning fossil fuels is the main source of carbon dioxide (CO2) in the atmosphere, releasing large amounts of this greenhouse gas into the air.

Which process is primarily responsible for the removal of carbon dioxide (CO2) from the atmosphere?

• Photosynthesis

• Combustion

• Cellular respiration

• Decomposition

Answer explanation

Photosynthesis is primarily responsible for the removal of carbon dioxide (CO2) from the atmosphere by converting it into oxygen and glucose through the process of using sunlight to synthesize nutrients from carbon dioxide and water.

Tags

NGSS.MS-LS1-6

Which human activity is a major contributor to the rise of carbon dioxide (CO2) levels in the atmosphere?

• Deforestation

• Fishing

• Urbanization

• Mining

Answer explanation

Deforestation is a major contributor to the rise of carbon dioxide (CO2) levels in the atmosphere by reducing the number of trees that absorb CO2 during photosynthesis.

Tags

NGSS.MS-ESS3-5

What happens to dead plants and animals over time?

• They turn into rocks

• • They release carbon dioxide through respiration

• • They decompose and return carbon to the soil and atmosphere

• • They are eaten by other animals

Answer explanation

Dead plants and animals decompose over time, returning carbon to the soil and atmosphere. This process is essential for nutrient cycling in ecosystems.

Tags

NGSS.MS-LS2-3

Which of the following is a natural process that releases carbon dioxide (CO2) into the atmosphere?

• Photosynthesis

• Cellular respiration

• Combustion

• Decomposition

Answer explanation

Respiration is a natural process that releases carbon dioxide (CO2) into the atmosphere through the breathing of living organisms.

Tags

NGSS.HS-LS1-7

What is the role of oceans in the carbon cycle?

• They only release carbon dioxide

• They absorb and store carbon dioxide

• They do not interact with carbon dioxide

• They convert carbon dioxide into oxygen

Answer explanation

Oceans play a crucial role in the carbon cycle by absorbing and storing carbon dioxide, helping to regulate the Earth's climate.

Tags

NGSS.HS-ESS2-6

Which of the following is a human activity that reduces the amount of carbon dioxide (CO2) in the atmosphere?

• Burning fossil fuels

• Deforestation

• Planting trees

• Industrialization

Answer explanation

Planting trees is a human activity that reduces the amount of carbon dioxide in the atmosphere by absorbing CO2 during photosynthesis.

Tags

NGSS.MS-LS1-6

How do plants contribute to the carbon cycle?

• By releasing carbon dioxide during photosynthesis

• By absorbing carbon dioxide during photosynthesis

• By converting carbon dioxide into methane

• By storing carbon dioxide in their roots

Answer explanation

By absorbing carbon dioxide during photosynthesis

Tags

NGSS.MS-LS1-6

What is the impact of deforestation on the carbon cycle?

• It increases the amount of carbon dioxide in the atmosphere

• It decreases the amount of carbon dioxide in the atmosphere

• It has no effect on the carbon cycle

• It converts carbon dioxide into oxygen

Answer explanation

Deforestation leads to the release of stored carbon in trees, increasing the amount of carbon dioxide in the atmosphere.

Tags

NGSS.HS-ESS2-6

NGSS.HS-LS2-5

Carbon exists in many forms on Earth.

• True

• False

Answer explanation

Carbon exists in many forms on Earth, making the statement true.

Tags

NGSS.MS-LS1-6

NGSS.MS-LS2-3

NGSS.MS-ESS2-1