For each of the following qustions four chices have been provided. Select the correct alternatives.
Carbon dioxide from atmosphere reaches the biotic component through ________

Options

A. respiration
B. photosynthesis
C. decomposition
D. fossil fuel burning

Answer

To answer the question "Carbon dioxide from the atmosphere reaches the biotic component through ________", we need to analyze the options provided and understand the processes involved.

### Step-by-Step Solution:

1. **Understanding Carbon Dioxide (CO2)**: Carbon dioxide is a gas present in the atmosphere. It plays a crucial role in various biological processes.

2. **Identifying the Biotic Component**: The biotic component refers to living organisms, particularly plants in this context, since they utilize carbon dioxide.

3. **Evaluating the Options**:
- **Option A: Respiration**: This is a process where organisms convert sugar into energy, releasing carbon dioxide back into the atmosphere. Therefore, respiration does not bring CO2 into the biotic component.
- **Option B: Photosynthesis**: This is the process by which plants use sunlight to convert carbon dioxide and water into glucose (sugar) and oxygen. In this process, carbon dioxide is absorbed by plants, making it a key method through which CO2 reaches the biotic component.
- **Option C: Decomposition**: This process involves the breakdown of dead organic matter, which releases carbon dioxide back into the atmosphere. It does not involve the uptake of CO2 by living organisms.
- **Option D: Fossil Fuel Burning**: This process releases carbon dioxide into the atmosphere but does not involve the absorption of CO2 by living organisms.

4. **Conclusion**: The only process that allows carbon dioxide from the atmosphere to be utilized by living organisms (the biotic component) is photosynthesis.

### Final Answer:
Carbon dioxide from the atmosphere reaches the biotic component through **photosynthesis**.

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