Biological control of agricultural pests, unlike chemical controls is

Options

A. Toxic
B. Polluting
C. Self perpetuating
D. Very expensive

Answer

### Step-by-Step Solution:

1. **Understanding Biological Control**: Biological control refers to the use of living organisms, such as predators, parasites, or pathogens, to manage agricultural pests. This method leverages natural relationships in the ecosystem to keep pest populations in check.

2. **Comparison with Chemical Control**: Chemical control involves the use of synthetic pesticides to eliminate pests. While effective, these chemicals can have harmful side effects, such as toxicity to non-target species, pollution of the environment, and the potential for pests to develop resistance.

3. **Key Characteristics of Biological Control**:
- **Non-toxic**: Biological control agents are generally non-toxic to humans and other non-target organisms, unlike many chemical pesticides.
- **Self-perpetuating**: Once introduced into the ecosystem, biological control agents can reproduce and maintain their population without the need for continuous human intervention. This is a significant advantage over chemical controls, which require repeated applications.
- **Less Pollution**: Biological control methods tend to be less polluting compared to chemical methods, which can contaminate soil and water.

4. **Evaluating the Options**:
- **Toxic**: Incorrect, as biological controls are generally non-toxic.
- **Polluting**: Incorrect, as biological controls are less likely to cause pollution.
- **Self-perpetuating**: Correct, as biological control agents can reproduce and sustain themselves in the environment.
- **Very Expensive**: Incorrect, as biological control methods can often be more cost-effective in the long run compared to repeated chemical applications.

5. **Conclusion**: Based on the characteristics of biological control and its comparison with chemical control, the correct answer to the question is that biological control is **self-perpetuating**.

### Final Answer:
Biological control of agricultural pests, unlike chemical controls, is **self-perpetuating**.

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