Bacteriophage is

Options

A. killer of virus
B. killer of bacteria
C. killer of monerans
D. eater of bacteria

Explanation

**Step-by-Step Solution:**

1. **Understanding Bacteriophage**: A bacteriophage, often referred to as a phage, is a type of virus that specifically infects bacteria.

2. **Literal Meaning**: The term "bacteriophage" is derived from Greek, where "bacteria" refers to bacteria and "phage" means to eat. Thus, the literal meaning of bacteriophage is "bacteria eater."

3. **Function of Bacteriophage**: Bacteriophages attach to bacterial cells and inject their genetic material into the bacteria. They then hijack the bacterial machinery to replicate themselves.

4. **Role of Lytic Enzymes**: In the tail region of the bacteriophage, there are enzymes known as lytic enzymes or lysins. These enzymes play a crucial role in the infection process by degrading the bacterial cell wall, allowing the bacteriophage to enter the bacterial cell.

5. **Conclusion**: Based on the above information, the correct characterization of a bacteriophage is that it is an "eater of bacteria." Therefore, the correct answer to the question is option 4: "eater of bacteria."

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