Question 1: Define the term 'carbon fixation' within the context of the carbon cycle.

Answer: Carbon fixation is the process by which autotrophs, such as plants, convert inorganic carbon dioxide into organic compounds during photosynthesis.

Question 2: Describe the role of decomposers in the carbon cycle.

Answer: Decomposers break down dead organic matter, releasing carbon dioxide back into the atmosphere through respiration.

Question 3: Explain how fossil fuels are involved in the carbon cycle.

Answer: Fossil fuels are formed from ancient organic matter and, when burned, release stored carbon dioxide into the atmosphere.

Question 1: A forest absorbs 15 tonnes of carbon dioxide per hectare per year through photosynthesis. Calculate the total amount of CO2 absorbed by a forest covering 50 hectares in one year. (Use the formula: Total absorption = absorption per hectare × number of hectares).

Answer: 750 tonnes

Question 2: If a factory releases 2000 kg of CO2 daily, how much CO2 is released in a non-leap year? (Assume 365 days). Show your calculation.

Answer: 730,000 kg

Question 1: Describe a simple experiment to investigate the effect of increased carbon dioxide levels on plant growth. Include the independent variable, dependent variable, and safety precautions.

Answer: An experiment could involve growing identical plants in controlled environments with varying levels of CO2. The independent variable is the CO2 concentration; the dependent variable is plant growth measured by height or biomass. Safety precautions include handling CO2 sources in well-ventilated areas and avoiding inhalation of high concentrations.

Question 1: In a study, a coastal ecosystem showed an increase in atmospheric CO2 levels from 400 ppm to 420 ppm over a decade. The carbon stored in the biomass increased by 15%. Explain possible reasons for this increase and its impact on the local ecosystem.

Answer: Possible reasons include increased photosynthesis due to higher CO2 availability, leading to greater biomass accumulation. This can enhance plant growth but may also alter species composition. The increase in biomass could support more wildlife; however, excess CO2 can contribute to climate change, affecting the ecosystem's long-term stability.

Question 1: Discuss how reforestation projects can help mitigate climate change by influencing the carbon cycle.

Answer: Reforestation increases the number of trees that absorb CO2 during photosynthesis, reducing atmospheric CO2 levels. This helps mitigate climate change by enhancing carbon sequestration and restoring ecosystems.

Question 2: Identify two industrial practices that contribute to increased carbon emissions and suggest one method to reduce each.

Answer: Practices include burning fossil fuels and deforestation. To reduce emissions, industries can adopt renewable energy sources and implement sustainable forestry practices.