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

Answer: The process by which carbon dioxide is converted into organic compounds by plants during photosynthesis.

Question 2: Describe two ways in which carbon is released back into the atmosphere from ecosystems.

Answer: Respiration by organisms and decomposition of organic matter.

Question 3: Explain why the carbon cycle is important for maintaining Earth's climate.

Answer: The carbon cycle regulates the amount of carbon dioxide in the atmosphere, which influences global temperatures and climate stability.

Question 1: A forest absorbs 1500 kg of carbon dioxide per hectare annually through photosynthesis. Calculate the amount of carbon fixed in tonnes per hectare per year. (1 tonne = 1000 kg)

Answer: 1.5

Question 2: If a decomposing organic matter releases 200 kg of carbon into the atmosphere per month, what is the annual emission in tonnes?

Answer: 2.4

Question 1: Describe a simple experiment to measure the rate of photosynthesis in a pondweed by collecting oxygen bubbles. Include key variables and safety precautions.

Answer: The experiment involves submerging pondweed in water under a light source and measuring the volume of oxygen bubbles produced over time. Variables include light intensity (independent), temperature, and CO2 concentration (controls). Safety precautions include handling water and electrical equipment carefully and avoiding spills.

Question 1: In a study, a grassland ecosystem fixed an average of 500 kg of carbon per hectare annually. Decomposition released 400 kg of carbon, and respiration by animals released 50 kg annually. What is the net carbon storage in this ecosystem?

Answer: Net carbon storage = Carbon fixed - (Decomposition + Respiration) = 500 - (400 + 50) = 50 kg.

Question 2: Interpret what the data suggests about the carbon balance in this ecosystem. Is it a carbon source or sink?

Answer: The ecosystem is acting as a carbon sink since it has a positive net carbon storage of 50 kg per hectare annually, meaning it stores more carbon than it releases.

Question 1: Describe how deforestation impacts the carbon cycle and global climate change.

Answer: Deforestation reduces the number of trees available to absorb carbon dioxide during photosynthesis, leading to higher atmospheric CO2 levels. This enhances the greenhouse effect, contributing to global warming and climate change.

Question 2: Multiple Choice: Which of the following is a major human activity that increases carbon emissions? A) Reforestation B) Burning fossil fuels C) Photosynthesis in plants D) Ocean absorption of CO2

Answer: B) Burning fossil fuels