Which of the following statements is not applicable to viruses?
(a) The virus replicates in a bacterial host.
(b) The protein coat of a virus does not enter the host cell.
(c) The genetic material is DNA or RNA.
(d) The virus replicates autonomously in the absence of a host.

Options

A. The virus replicates in a bacterial host.
B. The protein coat of a virus does not enter the host cell.
C. The genetic material is DNA or RNA.
D. The virus replicates autonomously in the absence of a host.

Answer

To determine which statement is not applicable to viruses, let's analyze each option step by step:

1. **Option A: The virus replicates in a bacterial host.**
- Viruses, particularly bacteriophages, are known to infect and replicate within bacterial hosts. This statement is true and applicable to viruses.

2. **Option B: The protein coat of a virus does not enter the host cell.**
- The protein coat, known as the capsid, typically remains outside the host cell when the virus infects it. Only the genetic material enters the host cell. This statement is also true and applicable to viruses.

3. **Option C: The genetic material is DNA or RNA.**
- Viruses can have either DNA or RNA as their genetic material. This is a defining characteristic of viruses. Thus, this statement is true and applicable to viruses.

4. **Option D: The virus replicates autonomously in the absence of a host.**
- Viruses are obligate parasites, meaning they cannot replicate or grow without a host. They require a host cell to provide the necessary machinery for replication. Therefore, this statement is not applicable to viruses.

Based on the analysis, the correct answer is:
**(d) The virus replicates autonomously in the absence of a host.**