The net primary productivity of an ecosystem can be viewed as the:

Options

A. standing biomass of all trophic levels.
B. amount of energy available to the consumers.
C. net growth of all consumers and producers.
D. total biomass available to .the decomposers.

Answer

**Step-by-Step Solution:**

1. **Understanding Net Primary Productivity (NPP)**:
- Net Primary Productivity refers to the amount of organic matter (biomass) produced by plants (producers) in an ecosystem after accounting for the energy lost through respiration. It is a measure of the energy available for consumption by herbivores (primary consumers) and higher trophic levels.

2. **Evaluating the Options**:
- **Option 1**: "Standing biomass of all trophic levels" - This is incorrect because standing biomass refers to the total mass of living matter at a given time, not the productivity or energy flow.
- **Option 2**: "Amount of energy available to consumers" - This is correct as it directly relates to NPP, which represents the energy available for the next trophic level after producers have used some for their own respiration.
- **Option 3**: "Net growth of all consumers" - This is incorrect because NPP specifically refers to producers, not consumers.
- **Option 4**: "Total biomass available to decomposers" - This is also incorrect as decomposers break down organic matter but do not directly relate to NPP.

3. **Conclusion**:
- After evaluating all the options, the correct answer is that the net primary productivity of an ecosystem can be viewed as the "amount of energy available to consumers."

**Final Answer**: The net primary productivity of an ecosystem can be viewed as the amount of energy available to consumers.

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