Secondary productivity is defined as

Options

A. the rate of production of orgainc matter during photosynthesis.
B. the available boimass for the consumption to heterotrophs.
C. the rate of formation of new organic matter by consumers.
D. gross primary productivity minus respiration losses.

Answer

To solve the question regarding the definition of secondary productivity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Secondary Productivity**:
- Secondary productivity refers to the rate at which consumers (heterotrophs) produce new organic matter or biomass. This is distinct from primary productivity, which is the rate at which autotrophs (like plants) produce organic matter through photosynthesis.

2. **Analyzing the Options**:
- **Option A**: "The rate of production of organic matter during photosynthesis" - This describes primary productivity, not secondary.
- **Option B**: "The available biomass for consuming two heterotrophs" - This does not accurately define secondary productivity.
- **Option C**: "The rate of formation of new organic matter by consumers" - This accurately describes secondary productivity, as it focuses on the biomass produced by heterotrophs.
- **Option D**: "Gross primary productivity minus respiration losses" - This describes net primary productivity, not secondary productivity.

3. **Identifying the Correct Answer**:
- Based on the analysis, the correct definition of secondary productivity is found in **Option C**: "The rate of formation of new organic matter by consumers."

### Final Answer:
**C. The rate of formation of new organic matter by consumers.**

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