Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth?

1. Volcanic action
2. Respiration
3. Photosynthesis
4. Decay of organic matter

Select the correct answer using the code given below.

1. 1 and 3 only
2. 2 only
3. 1, 2 and 4 only
4. 1, 2, 3 and 4

Explanation

Option (c) is correct

• Volcanic Action: Volcanic eruptions release large quantities of CO₂ into the atmosphere as part of the Earth’s geological processes.
• Respiration: Respiration by living organisms involves the breakdown of glucose, releasing CO₂ as a byproduct.
• Photosynthesis: This process involves plants, algae, and certain bacteria converting CO₂ and water into glucose and oxygen using sunlight. (Removes CO₂)
• Decay of Organic Matter: The decomposition of dead plants and animals by microorganisms releases CO₂ into the atmosphere.

Answer: (c) 1, 2 and 4 only; Difficulty Level: Easy