Ecological efficiency is

Options

A. Food primary assimilated/Food energy ingested `xx100`
B. Gross primary productivity/Incident total solar radiation `xx100`
C. Volume of `CO_(2)` evolved/volume of `O_(2)` consumed
D. Energy in biomass production at a trophic level/Energy in biomass production at previous trophical level `xx100`

Answer

**Step-by-Step Solution:**

1. **Understanding Ecological Efficiency**: Ecological efficiency refers to the efficiency with which energy is transferred from one trophic level to the next in an ecosystem. It is a measure of how much energy is available to the next trophic level after accounting for energy lost at the previous level.

2. **Identifying Types of Ecological Efficiency**: There are two main types of ecological efficiency:
- **Net Production Efficiency**: This is the efficiency with which organisms convert the energy they assimilate from food into biomass.
- **Gross Primary Productivity**: This refers to the total amount of chemical energy produced by primary producers (like plants) through photosynthesis.

3. **Analyzing the Options**: The question provides four options to define ecological efficiency:
- **Option A**: Food primary assimilated upon food energy ingested into 100
- **Option B**: Gross primary productivity upon incident total solar radiation into 100
- **Option C**: Volume of CO2 evolved upon volume of O2 consumed
- **Option D**: Energy in biomass production at a trophic level upon energy in biomass production at previous trophic level into 100

4. **Evaluating Each Option**:
- **Option A**: This option does not accurately represent ecological efficiency.
- **Option B**: This option relates to primary productivity but not directly to ecological efficiency.
- **Option C**: This option relates to respiration and does not define ecological efficiency.
- **Option D**: This option correctly describes ecological efficiency as it relates to the energy transferred from one trophic level to the next.

5. **Conclusion**: The correct answer is **Option D**: Energy in biomass production at a trophic level upon energy in biomass production at previous trophic level into 100.

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