The overall productivity in terrestrial ecosystems is limited by

Options

A. temperature
B. water
C. sunlight
D. a combination of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Productivity in Ecosystems**:
- Productivity refers to the rate at which energy is produced in an ecosystem, primarily through photosynthesis in plants. This energy is then transferred through the food chain.

2. **Identifying Factors Affecting Productivity**:
- Productivity in terrestrial ecosystems is influenced by various factors, which can be broadly categorized into abiotic (non-living) and biotic (living) factors.

3. **Examining Abiotic Factors**:
- Key abiotic factors include:
- **Temperature**: Affects metabolic rates and growth of organisms.
- **Water**: Essential for photosynthesis and nutrient transport.
- **Sunlight**: The primary energy source for photosynthesis.

4. **Considering Biotic Factors**:
- Biotic factors include:
- **Plant Species**: Different plants have varying capacities for photosynthesis and growth.
- **Herbivory**: The impact of herbivores on plant populations can limit productivity.
- **Competition**: Plants compete for resources like light, water, and nutrients.

5. **Conclusion**:
- The overall productivity in terrestrial ecosystems is limited by a combination of both abiotic and biotic factors. Therefore, the correct answer is that productivity is influenced by the interplay of temperature, water, sunlight, and various biotic factors.

**Final Answer**: The overall productivity in terrestrial ecosystems is limited by a combination of abiotic factors (temperature, water, sunlight) and biotic factors (plant species, herbivory, competition).

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