Limiting factor for growth of aquatic organisms is

Options

A. `CO_(2)`
B. `O_(2)`
C. Mineral elements
D. All the above.

Answer

### Step-by-Step Solution:

1. **Understanding Limiting Factors**:
- A limiting factor is a condition that can restrict the growth, abundance, or distribution of an organism or a population of organisms in an ecosystem. It can be biotic (living factors) or abiotic (non-living factors).

2. **Identifying the Context**:
- In the context of aquatic organisms, several factors can influence their growth. These include temperature, sunlight, oxygen content, nutrient availability, and salinity.

3. **Analyzing the Options**:
- The options provided are carbon dioxide, oxygen, mineral elements, and all of the above. We need to determine which of these is the primary limiting factor for aquatic organisms.

4. **Evaluating Each Option**:
- **Carbon Dioxide**: While it is essential for photosynthesis in aquatic plants, it does not directly limit the growth of all aquatic organisms.
- **Oxygen**: This is crucial for the respiration of aquatic animals. A decrease in oxygen levels can severely impact their growth and survival.
- **Mineral Elements**: These are necessary for various biological functions but are not the primary limiting factor.
- **All of the Above**: This option suggests that all listed factors limit growth, but we are looking for the most significant limiting factor.

5. **Conclusion**:
- Among the options, oxygen is identified as the primary limiting factor for the growth of aquatic organisms. A deficiency in oxygen can lead to decreased growth rates and can even be fatal for many aquatic species.

### Final Answer:
The limiting factor for the growth of aquatic organisms is **oxygen**.

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