According to blackman phtosynthesis is affected by several factors but the role of photosythesis is limited by the

Options

A. fastest step in the pathway
B. slowest step in the pathway
C. factor present in least amount
D. factor present in large amount

Answer

**Step-by-Step Solution:**

1. **Understanding Blackman's Law of Limiting Factors**: Blackman's law states that the rate of a process like photosynthesis is limited by the factor that is in the least favorable condition. This means that among various factors affecting photosynthesis (light intensity, carbon dioxide concentration, temperature, etc.), the one that is the least optimal will determine the overall rate of photosynthesis.

2. **Identifying Factors Affecting Photosynthesis**: The primary factors that can affect the rate of photosynthesis include:
- Light intensity
- Carbon dioxide concentration
- Temperature
- Water availability
- Nutrient availability

3. **Determining the Limiting Factor**: According to Blackman's law, if one of these factors is at a suboptimal level (for example, low light intensity), it will limit the rate of photosynthesis even if the other factors are at optimal levels. For instance, if light intensity is low while temperature and CO2 levels are high, the low light intensity will be the limiting factor.

4. **Conclusion**: Therefore, the role of photosynthesis is limited by the slowest factor, which is the one that is least favorable or in the least amount. This is the essence of Blackman's law of limiting factors.

5. **Final Answer**: According to Blackman, the role of photosynthesis is limited by the slowest factor.

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