How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

Options

A. 0.01
B. 0.1
C. 0.4
D. 0.9

Explanation

To solve the question of how much of the net primary productivity (NPP) of a terrestrial ecosystem is eaten and digested by herbivores, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Net Primary Productivity (NPP)**:
- NPP refers to the amount of energy or biomass that plants produce through photosynthesis, minus the energy they use for respiration. It represents the energy available to the next trophic levels, including herbivores.

2. **Apply the 10% Law of Energy Transfer**:
- The 10% law states that only about 10% of the energy from one trophic level is transferred to the next. This means that when plants (producers) convert solar energy into chemical energy, only a fraction of that energy is passed on to herbivores (primary consumers).

3. **Calculate Energy Available to Herbivores**:
- If we assume that plants utilize 1% of the total energy received from the sun (for example, if the sun provides 100,000 joules, then plants use 1,000 joules), then:
- Energy available to herbivores = 10% of the NPP.
- Therefore, if NPP is 1,000 joules, the energy available to herbivores would be:
\[ \text{Energy to herbivores} = 10\% \times 1000 \text{ joules} = 100 \text{ joules} \]

4. **Convert the Percentage to Decimal**:
- To express 10% as a decimal, divide by 100:
\[ 10\% = \frac{10}{100} = 0.1 \]

5. **Select the Correct Option**:
- Based on the calculations, the amount of NPP that is eaten and digested by herbivores is 0.1.

### Final Answer:
The correct answer is **0.1**.

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