Which of the following statements describe a bacteriophage correctly?

Options

A. It is a bacterium which causes diseases in plants.
B. It is a type of virus which attacks bacteria.
C. It is a bacterium which kills viruses.
D. It can multiply inside both living and non living cells.

Answer

To determine which statements correctly describe a bacteriophage, let's analyze each option step by step:

1. **Statement 1: Bacterium which causes disease in plants.**
- This statement is incorrect. A bacteriophage is not a bacterium; it is a type of virus that specifically infects bacteria. Therefore, it cannot be described as a bacterium that causes disease in plants.

2. **Statement 2: Virus which attacks bacteria.**
- This statement is correct. Bacteriophages are indeed viruses that specifically target and infect bacterial cells. They attach to bacteria and inject their genetic material, leading to the destruction of the bacterial cell.

3. **Statement 3: Bacteria which kills virus.**
- This statement is incorrect. Bacteriophages are not bacteria; they are viruses. They do not kill viruses; instead, they infect and kill bacteria.

4. **Statement 4: Multiplies inside both living and non-living cells.**
- This statement is incorrect. Bacteriophages can only multiply inside living cells (specifically bacterial cells). Outside of a host, they do not replicate and behave as inert particles.

Based on the analysis, the only correct statement that describes a bacteriophage is **Statement 2: Virus which attacks bacteria.**

### Summary of the Solution:
- Statement 1: Incorrect (bacteriophage is a virus, not a bacterium).
- Statement 2: Correct (bacteriophages are viruses that attack bacteria).
- Statement 3: Incorrect (bacteriophages are not bacteria and do not kill viruses).
- Statement 4: Incorrect (bacteriophages multiply only inside living cells).