NPP (net primary productivity) is highest in

Options

A. Tropical region
B. Polar region
C. High altitude
D. Deep ocean

Answer

To determine where net primary productivity (NPP) is highest, we can analyze the options provided:

1. **Understanding NPP**:
- Net Primary Productivity (NPP) is the rate at which all the plants in an ecosystem produce net useful chemical energy. It is calculated by subtracting the energy used by plants for respiration from the total energy produced through photosynthesis (Gross Primary Productivity).
- NPP = Gross Primary Productivity - Respiration by plants

2. **Evaluating the Options**:
- **Tropical Region**: Tropical regions, particularly tropical rainforests, are known for their high levels of biodiversity and dense vegetation. They receive ample sunlight and rainfall, which contribute to high rates of photosynthesis. This results in a high NPP because the energy stored as organic matter is substantial.
- **Polar Region**: Polar regions have extreme climates with limited sunlight and shorter growing seasons, leading to lower rates of photosynthesis and consequently lower NPP.
- **High Altitude**: High altitude regions often have harsh climates, lower temperatures, and shorter growing seasons, which also contribute to lower NPP.
- **Deep Ocean**: While some areas of the ocean can be productive, overall, deep ocean regions have lower light availability and nutrient levels, leading to lower NPP compared to terrestrial ecosystems like tropical rainforests.

3. **Conclusion**:
- Based on the analysis, the highest NPP is found in the **tropical region**, specifically in tropical rainforests due to their favorable conditions for plant growth and photosynthesis.

**Final Answer**: NPP (net primary productivity) is highest in the **tropical region**.

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