Which process will NOT release carbon dioxide into the atmosphere?

Analyze the question: You are asked to find the process that does NOT release CO₂ into the atmosphere. Four options add CO₂ to the air, and one removes it.

Explain the concept: The carbon cycle has two sides:

• Processes that release CO₂: burning (combustion), respiration, exhalation, and decay or putrefaction.
• Processes that remove CO₂: photosynthesis.

Step-by-step solution:

• A. Burning: Combustion of fuels, wood, and so on gives off CO₂. It releases CO₂.
• B. Exhalation: The air we breathe out contains CO₂ produced by respiration. It releases CO₂.
• C. Photosynthesis: Green plants take in CO₂ and water, and with light energy they make glucose and oxygen: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ CO₂ is used up, not released. This is the answer.
• D. Putrefaction: Bacteria and fungi decompose dead organic matter, and CO₂ is released. It releases CO₂.
• E. Respiration: Glucose is broken down to release energy, and CO₂ is a by-product: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy. It releases CO₂.

Answer: C. Photosynthesis

Exam tip: Remember that photosynthesis takes in CO₂, while burning, respiration, and decay give it out. When a question asks which process does NOT release CO₂, look for photosynthesis. Always read the word "NOT" carefully, because it is easy to lose marks by missing it.