______ proposed the 'law' of limiting factors.

Explanation

**Step-by-Step Solution:**

1. **Identify the Scientist**: The question asks who proposed the 'law' of limiting factors. The scientist who proposed this law is Blackman.

2. **Understand the Law of Limiting Factors**: Blackman's law of limiting factors states that the rate of a process (like photosynthesis) is determined by the factor that is in the least supply, or the minimum requirement. This means that even if other factors are abundant, the one that is least available will limit the overall rate of the process.

3. **Application to Photosynthesis**: In the context of photosynthesis, this law implies that if one of the necessary components (like carbon dioxide or water) is in short supply, it will limit the rate at which photosynthesis can occur, regardless of the availability of other components.

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