Question

Which of the following contribute(s) to the carbon cycle? a. respiration b. photosynthesis c. fossil fuel combustion d. decomposition of dead organisms e. All of these are correct.

Short answer

The correct answer is e: All of these are correct. Each option (respiration, photosynthesis, fossil fuel combustion, and decomposition of dead organisms) contributes to the carbon cycle in a different way, but all are involved in the process of moving carbon through the Earth's systems.

Step-by-step solution

Option a: Respiration

Respiration is the process where organisms take in oxygen and release carbon dioxide, which returns carbon to the atmosphere. Therefore, respiration contributes to the carbon cycle.

Option b: Photosynthesis

Photosynthesis is the process by which plants, algae, and some bacteria use sunlight energy to convert carbon dioxide from the atmosphere into organic compounds (carbon-based molecules), thus consuming carbon and integrating it into their biomass. Therefore, photosynthesis contributes to the carbon cycle.

Option c: Fossil fuel combustion

Fossil fuel combustion is the process of burning fossil fuels, such as coal, oil, and natural gas, to release energy. During this process, carbon dioxide is released back into the atmosphere, contributing to the carbon cycle.

Option d: Decomposition of dead organisms

Decomposition is the process where dead organisms are broken down into their respective components by decomposers such as bacteria and fungi. This process releases the carbon stored in these organisms back into the atmosphere or the soil in the form of carbon dioxide or organic compounds, thus contributing to the carbon cycle.

Conclusion

Since all the options (a, b, c, d) contribute to the carbon cycle, the correct answer is option e: All of these are correct.