In the global carbon cycle, what is the primary role of photosynthesis carried out by green plants, algae, and some bacteria?

Introduction / Context:
The carbon cycle describes how carbon moves between atmosphere, living organisms, oceans, and rocks. Photosynthesis is one of the most important processes in this cycle. This question asks what role photosynthesis plays in moving carbon between different parts of the Earth system.

Given Data / Assumptions:

• Photosynthesis occurs in green plants, algae, and some bacteria.
• These organisms use light energy to drive chemical reactions.
• The options describe different ways carbon might move in the cycle.
• We assume basic knowledge that photosynthesis uses carbon dioxide as a raw material.

Concept / Approach:
In photosynthesis, plants take in carbon dioxide from the air and water from the soil, and use light energy to form glucose and other organic molecules. Oxygen is released as a by product. In this way, photosynthesis removes carbon dioxide from the atmosphere and stores carbon in the biomass of plants and, indirectly, in animals that eat those plants. It does not release carbon from fossil fuels or move carbon directly from rocks into the air. Therefore, the correct description is that photosynthesis takes carbon out of the atmosphere and stores it in organic matter.

Step-by-Step Solution:

Verification / Alternative check:
Diagrams of the carbon cycle in textbooks show arrows pointing from the atmosphere to plants labelled photosynthesis, indicating uptake of carbon dioxide. Arrows from plants to animals show feeding, and arrows from plants and animals back to the atmosphere through respiration and decomposition show carbon returning as carbon dioxide. The central role of photosynthesis in moving carbon from air into the living biosphere supports the chosen answer.

Why Other Options Are Wrong:

• Releasing carbon from fossil fuels is wrong because that process is called combustion, not photosynthesis.
• Directly converting carbonates in rocks into carbon dioxide is wrong because that involves geological processes, not plant photosynthesis.
• Moving carbon only from animals back into rocks is wrong and describes neither the main role of photosynthesis nor the real carbon pathways.

Common Pitfalls:
Some learners mix up the roles of photosynthesis and respiration. Respiration releases carbon dioxide back into the atmosphere, while photosynthesis removes carbon dioxide and turns it into organic matter. Remember the simple contrast: photosynthesis stores carbon, while respiration and combustion return it.

Final Answer:
It removes carbon dioxide from the atmosphere and stores carbon in organic molecules like sugars