Which method of cellular defence is common in almost all eukaryotic organisms ?

Options

A. RNA interference
B. Reverse transcription
C. VNTR
D. Phagocytosis

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a method of cellular defense that is common in almost all eukaryotic organisms.

2. **Analyzing the Options**: The options provided are:
- A) RNA interference
- B) Reverse transcription
- C) VNTR (Variable Number Tandem Repeats)
- D) Phagocytosis

3. **Evaluating Each Option**:
- **Option A: RNA interference**: This is a genetic mechanism that suppresses gene expression by degrading complementary mRNA sequences. It is a common defense mechanism in eukaryotic cells.
- **Option B: Reverse transcription**: This process involves converting mRNA into DNA. It is not a defense mechanism but rather a normal cellular process.
- **Option C: VNTR**: This refers to variations in the number of tandem repeats in DNA sequences. It does not serve as a cellular defense mechanism.
- **Option D: Phagocytosis**: This is the process by which certain cells (like macrophages) engulf and digest pathogens. While it is a defense mechanism, it is not as universally applicable to all eukaryotic organisms as RNA interference.

4. **Conclusion**: After evaluating the options, RNA interference is identified as the common method of cellular defense in almost all eukaryotic organisms.

5. **Final Answer**: The correct answer is **A) RNA interference**.

---