`("NPP/GPP") xx 100` is

Options

A. Assimilation efficiency
B. Net production efficiency
C. Ecological efficiency
D. Photosynthetic efficiency

Answer

To solve the question regarding the expression \((\text{NPP/GPP}) \times 100\), we will break it down step by step:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **NPP (Net Primary Productivity)**: This is the amount of energy that remains after the plants have used some of the energy for their own respiration. It represents the energy available for the next trophic levels in the ecosystem.
- **GPP (Gross Primary Productivity)**: This is the total amount of energy captured by photosynthesis in a given area over a certain time period. It includes all the energy that plants produce.

2. **Formula Explanation**:
- The formula \((\text{NPP/GPP}) \times 100\) is used to calculate the efficiency of energy conversion in plants. It shows what percentage of the gross primary productivity is converted into net primary productivity.

3. **Calculate the Ratio**:
- When you divide NPP by GPP, you are essentially finding out how much of the energy captured (GPP) is actually available for growth and reproduction (NPP).

4. **Multiply by 100**:
- Multiplying the ratio by 100 converts it into a percentage, which is a common way to express efficiency.

5. **Interpret the Result**:
- The result of this calculation gives you the **Assimilation Efficiency** or **Productivity Efficiency** of the plants. It indicates how effectively plants convert the energy they capture into biomass.

### Conclusion:
Thus, \((\text{NPP/GPP}) \times 100\) represents the **Assimilation Efficiency** or **Productivity Efficiency** of plants.