Primary productivity does not depend upon

Options

A. Plant species
B. environmental factors
C. herbivore species
D. availability of nutrients .

Answer

To determine which factor primary productivity does not depend upon, we need to analyze the components involved in primary productivity.

### Step-by-Step Solution:

1. **Understanding Primary Productivity**:
- Primary productivity refers to the amount of organic matter (biomass) produced by plants through photosynthesis in a given area over a specific time period.

2. **Factors Affecting Primary Productivity**:
- **Plant Species**: Different plant species have varying capacities for photosynthesis and biomass production. Therefore, primary productivity is influenced by the types of plants present in an ecosystem.
- **Environmental Factors**: These include light, temperature, water availability, and climate conditions, all of which significantly affect plant growth and photosynthesis.
- **Availability of Nutrients**: Nutrients such as nitrogen, phosphorus, and potassium are essential for plant growth. A lack of these nutrients can limit primary productivity.

3. **Identifying the Irrelevant Factor**:
- **Herbivore Species**: While herbivores depend on plants for food, they do not directly influence the primary productivity of plants. Their presence may affect plant biomass indirectly through grazing, but they do not contribute to the production of biomass.

4. **Conclusion**:
- Among the given options, primary productivity does not depend on herbivore species.

### Final Answer:
Primary productivity does not depend on **herbivore species**.