Lesson Worksheet: The Carbon Cycle Biology

In this worksheet, we will practice describing the process of the carbon cycle, and explaining its importance for living organisms.

Q1:

Which of the following processes removes carbon dioxide from the atmosphere?

  • ACombustion
  • BDecomposition
  • CPhotosynthesis
  • DRespiration

Q2:

Carbon is an important element for all living organisms. What process allows plants to take in carbon dioxide from the atmosphere and convert it into glucose and oxygen?

  • ARespiration
  • BPhotosynthesis
  • CDecomposition
  • DTranspiration
  • ETranslocation

Q3:

Which of the following best explains where fossil fuels come from?

  • AFossil fuels are formed when dead plants and animals are exposed to high pressure and low temperatures over 10–20 years.
  • BFossil fuels are formed when organic matter is burnt.
  • CFossil fuels are formed from the excretions of decomposers after they have broken down dead organisms.
  • DFossil fuels are formed when dead plants and animals are exposed to high pressure and high temperatures over millions of years.

Q4:

Carbon from organic matter is stored in fossil fuels, like coal and oil. Which of the following processes releases this carbon as carbon dioxide into the atmosphere?

  • ADegradation
  • BAmmonification
  • CCombustion
  • DRespiration

Q5:

Which of the following processes is not part of the naturally occurring carbon cycle?

  • ADecomposition
  • BPhotosynthesis
  • CRespiration
  • DCombustion of fossil fuels
  • EConsuming plants/other animals

Q6:

The picture provided shows a group of fungi. What role do fungi have in the carbon cycle?

Group of fungi (hypholoma fasciculare)-72ppl
  • AFungi act as decomposers and break down carbon-containing organic matter.
  • BFungi photosynthesize and remove carbon dioxide from the atmosphere.
  • CFungi consume other organisms that contain carbon and excrete it to recycle it.
  • DFungi store large amounts of carbon and can be burnt as fuel sources.

Q7:

Decomposers, like the fungi pictured, release carbon dioxide into the atmosphere. What biological process carried out by these decomposers releases carbon dioxide?

Pink Burn Cup mushrooms
  • ADegradation
  • BTranspiration
  • CVentilation
  • DPhotosynthesis
  • ERespiration

Q8:

When plants and animals die, they usually decompose. Alternatively, they can be subjected to low oxygen and high pressure, which can compress their hard body parts. What is formed when such compression happens?

  • AFossils
  • BWater
  • CBacteria
  • DManure
  • ENew organisms

Q9:

The graph provided shows the changes in atmospheric carbon dioxide levels over time. Which of the following statements best explains these changes in the atmosphere?

  • AThe levels of carbon dioxide have increased since 1990 because there are more trees and plants on the earth that release carbon dioxide through respiration.
  • BThe levels of carbon dioxide have increased substantially since 1950 because animals are releasing more carbon dioxide through respiration.
  • CThe levels of carbon dioxide have increased substantially since 1950 because human activities have increased the combustion of fossil fuels.
  • DThe levels of carbon dioxide have remained relatively constant since 1990 because the levels of human activities that release carbon dioxide have decreased.

Q10:

The graph shows the approximate percentage of the UK land covered by forest over time. Which of the following best explains the impact this trend could have on the UK carbon cycle?

  • AA decrease in trees means less carbon will be removed from the atmosphere by respiration.
  • BA decrease in trees means less carbon will be removed from the atmosphere by photosynthesis.
  • CThe number of trees will not affect the carbon cycle.

This lesson includes 9 additional questions for subscribers.

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