Why is the rate of assimilation of energy at the herbivore level called secondary productivity? 

Explanation

To understand why the rate of assimilation of energy at the herbivore level is called secondary productivity, we can break down the concept into several steps:

### Step-by-Step Solution:

1. **Definition of Productivity**:
- Productivity in an ecosystem refers to the rate at which energy is converted into biomass by producers and consumers.

2. **Primary Productivity**:
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