The amount of biomass or organic matter produced per unit area over a time period by the plants during photosynthesis is called

Options

A. Primary productivity
B. Secondary productivity
C. Standing state
D. Standing crop

Answer

To solve the question, we need to identify the term that describes the amount of biomass or organic matter produced per unit area over a specific time period by plants during photosynthesis.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- We need to understand the definitions of the terms provided in the options: primary productivity, secondary productivity, standing state, and standing crop.

2. **Defining Primary Productivity**:
- Primary productivity refers to the rate at which biomass is produced by autotrophs (like plants) during photosynthesis. It is measured as the amount of organic matter produced per unit area over a specific time period.

3. **Evaluating Other Options**:
- **Secondary Productivity**: This refers to the rate of formation of new organic matter by consumers (herbivores and carnivores) and is not relevant to the question.
- **Standing State**: This term refers to the amount of nutrients present in the soil at any given time, which does not pertain to biomass production.
- **Standing Crop**: This refers to the total mass of living material (biomass) present at a specific time in a particular area, but it does not measure the rate of production over time.

4. **Conclusion**:
- Based on the definitions, the correct answer to the question is **Primary Productivity**, as it specifically refers to the biomass produced by plants through photosynthesis over a given area and time.

### Final Answer:
The amount of biomass or organic matter produced per unit area over a time period by the plants during photosynthesis is called **Primary Productivity**.