Give the productivity of tropical rain forests.

Explanation

### Step-by-Step Solution:

1. **Understanding Productivity**:
- Productivity in an ecosystem refers to the rate at which energy is produced by photosynthetic organisms, typically measured in terms of biomass or energy (kcal) produced per unit area per year.

2. **Identifying the Ecosystem**:
- The question specifically asks about the productivity of tropical rainforests, which are known for their rich biodiversity and high levels of primary productivity.

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