Which one of the following is the most productive ecosystem?

Options

A. Temperate forest
B. Grasslands
C. Desert
D. Tropical rainforest

Explanation

**Step-by-Step Solution:**

1. **Understanding Ecosystem Productivity**: The question asks us to identify the most productive ecosystem among the given options. Productivity in ecosystems is often measured in terms of Net Primary Productivity (NPP), which is the amount of organic matter produced by photosynthetic organisms after accounting for the energy used in respiration.

2. **Evaluating Each Option**:
- **Temperate Forest**: This ecosystem, also known as broadleaf forest, has significant respiratory losses. Due to high respiration rates, a large amount of biomass is not available for heterotrophs, resulting in lower productivity. Thus, temperate forests have low NPP.

- **Grassland**: Grasslands do not accumulate much organic matter, leading to low production of biomass. Consequently, the NPP of grasslands is also low, making it an unsuitable option for the most productive ecosystem.

- **Desert**: Deserts are characterized by low nutrient availability and extreme conditions, which contribute to low productivity. The NPP in desert ecosystems is low, indicating that they are not productive ecosystems.

- **Tropical Forest**: Tropical forests are known for their rich biodiversity and high availability of resources such as soil moisture and nutrients. This leads to high primary productivity and a stable ecosystem. Therefore, tropical forests have the highest NPP among the options provided.

3. **Conclusion**: After evaluating all the options, the tropical forest emerges as the most productive ecosystem due to its high NPP and stable environmental conditions.

**Final Answer**: The most productive ecosystem is the **tropical forest**.

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