From which of the following most of the natural antibiotics are prepared?

Options

A. Phycomycetes
B. Streptonmyces
C. Actinomycetes
D. Archaebacteria

Answer

To answer the question "From which of the following most of the natural antibiotics are prepared?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify which organism is the primary source of natural antibiotics from the given options: Phycomycetes, Streptomyces, Actinomycetes, and Archaeobacteria.

2. **Define Antibiotics**: Antibiotics are substances that can kill or inhibit the growth of bacteria. They are crucial in treating bacterial infections.

3. **Analyze the Options**:
- **Phycomycetes**: This group includes certain fungi, but they are not the main source of antibiotics.
- **Streptomyces**: This is a genus of bacteria known for producing a large number of antibiotics.
- **Actinomycetes**: This is a broader group that includes Streptomyces, but not all actinomycetes produce antibiotics.
- **Archaeobacteria**: These are a group of microorganisms that are not typically associated with antibiotic production.

4. **Identify the Correct Answer**: Among the options, **Streptomyces** is the most significant source of natural antibiotics, accounting for approximately 80% of them. The first antibiotic discovered from this genus was Streptomycin in 1943.

5. **Conclusion**: Based on the analysis, the correct answer to the question is **B. Streptomyces**.