Consider the following:1. Photosynthesis2. Respiration3. Decay of organic matter4. Volcanic actionWhich of the above add carbon dioxide to the carbon cycle on Earth?
✓ Correct answer: c) 2, 3 and 4 only
ExplanationThe carbon cycle is a natural process that involves the movement of carbon between the atmosphere, oceans, soil, rocks, and living organisms.Respiration, decay of organic matter, volcanic action, fossil fuel combustion, deforestation, ocean-atmosphere exchange adds carbon to the cycle.All living organisms (plants, animals, and microorganisms) respire and breaking down glucose and oxygen to release energy, CO₂, and water.This process adds carbon dioxide to the atmosphere.When dead plants, animals, and other organic materials decompose microbes break them down.During decomposition CO₂ and methane (CH₄) are released into the atmosphere.Volcanic eruptions release stored carbon dioxide from the Earth’s mantle into the atmosphere.This is a natural source of CO₂ emissions.During photosynthesis plants, algae, and some bacteria absorb CO₂ from the atmosphere and use sunlight to convert it into glucose and oxygen.This process removes carbon dioxide from the atmosphere rather than adding it.371
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