Living organisms used to enrich the nutrient quality of the soil are called as

Options

A. bicontrol agents
B. biofertilisers
C. synthetic fertilisers
D. natural ferilisers

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks for the term used to describe living organisms that enrich the nutrient quality of the soil.

2. **Identifying Relevant Terms:**
- The question hints at fertilizers that contain living organisms.
- We need to differentiate between various types of fertilizers and their components.

3. **Analyzing Different Types of Fertilizers:**
- **Biocontrol Agents:** These protect plants from pests but do not contain living organisms that enrich soil nutrients. Hence, they are not the answer.
- **Biofertilizers:** These are substances that contain living microorganisms. They promote plant growth and enrich the nutrient quality of the soil. This fits the criteria of the question.
- **Synthetic Fertilizers:** These are chemical substances that do not contain living organisms. Therefore, they cannot be the answer.
- **Natural Fertilizers:** While these are derived from animal or vegetable matter and may contain some living organisms, they are primarily composed of organic matter and do not specifically refer to living organisms that enrich the soil.

4. **Conclusion:** Based on the analysis, the correct answer is **biofertilizers**, as they are specifically defined as substances containing living microorganisms that enhance soil nutrient quality.

**Final Answer:** Living organisms used to enrich the nutrient quality of the soil are called **biofertilizers**.

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