____ is the rate of production of organic matter by consumers.

Options

A. Primary productivity
B. secondary productivity
C. Net primary productivity
D. Gross primary productivity.

Explanation

To solve the question, "____ is the rate of production of organic matter by consumers," we need to analyze the provided options and understand the definitions of each term related to productivity in an ecosystem.

### Step-by-Step Solution:

1. **Understand the Terms:**
- **Primary Productivity:** This refers to the rate at which solar energy is converted into organic matter by producers (like plants) through photosynthesis.
- **Gross Primary Productivity (GPP):** This is the total amount of organic matter produced by producers before any losses due to respiration.
- **Net Primary Productivity (NPP):** This is the amount of organic matter available after accounting for the energy used by producers for respiration. It represents the biomass available for consumers (herbivores and decomposers).
- **Secondary Productivity:** This refers to the rate of production of organic matter by consumers (herbivores and carnivores) in the ecosystem.

2. **Identify the Correct Option:**
- The question specifically asks for the rate of production of organic matter **by consumers**.
- From our definitions, we see that **secondary productivity** is the term that describes the production of organic matter by consumers.

3. **Conclusion:**
- Therefore, the correct answer to the question is **secondary productivity**.

### Final Answer:
**Secondary productivity** is the rate of production of organic matter by consumers.

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