Antibiotics are obtained from

Options

A. bacteria
B. fungi
C. actinomycetes
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Antibiotics**: Antibiotics are substances that can kill or inhibit the growth of bacteria. They are primarily used to treat bacterial infections.

2. **Identifying Sources of Antibiotics**: Antibiotics can be derived from various microorganisms. The main sources include:
- **Bacteria**: Certain bacteria produce antibiotics. For example, Streptomyces is a genus of bacteria known for producing several antibiotics, including streptomycin.
- **Fungi**: Some fungi are also known to produce antibiotics. A well-known example is the Penicillium fungus, which produces penicillin, one of the first antibiotics discovered.
- **Actinomycetes**: This group of bacteria, which is similar to fungi, is also a significant source of antibiotics. They are known for producing a variety of antibiotic compounds.

3. **Evaluating the Options**: The question provides four options:
- A) Bacteria
- B) Fungi
- C) Actinomycetes
- D) All of these

4. **Conclusion**: Since antibiotics can be obtained from bacteria, fungi, and actinomycetes, the correct answer is D) All of these.

**Final Answer**: Antibiotics are obtained from all of these: bacteria, fungi, and actinomycetes.

---