Which of the following statements is false about viruses-

Options

A. Viruses are obligate parasites
B. Viruses can multiply only when they are inside the living cells
C. Viruses cannot pass bacterial proof filters
D. Viruses are made up of protein + DNA or RNA (nerver both DNA and RNA)

Answer

To determine which statement about viruses is false, we will analyze each of the provided options step by step.

### Step 1: Analyze Option 1
**Statement:** Viruses are obligate parasites.
**Analysis:** This statement is true. Viruses require a host cell to replicate and cannot reproduce independently. They are considered obligate parasites because they depend on a living host for their life cycle.

**Hint:** Remember that obligate parasites need a host to survive and reproduce.

### Step 2: Analyze Option 2
**Statement:** Viruses can multiply only when they are inside the living cell.
**Analysis:** This statement is also true. Viruses cannot replicate outside of a host cell; they must infect a living cell to reproduce and propagate.

**Hint:** Think about how viruses function; they need to hijack a host's cellular machinery to multiply.

### Step 3: Analyze Option 3
**Statement:** Viruses cannot pass bacterial proof filters.
**Analysis:** This statement is false. Viruses are much smaller than bacteria and can pass through bacterial proof filters, which are designed to block larger microorganisms like bacteria. Viruses typically range in size from about 20 to 300 nanometers, while bacteria are much larger.

**Hint:** Consider the size difference between viruses and bacteria; this will help clarify their ability to pass through filters.

### Step 4: Analyze Option 4
**Statement:** Viruses are made up of proteins plus DNA and RNA. Never both DNA and RNA.
**Analysis:** This statement is true. Viruses can contain either DNA or RNA as their genetic material, but they do not contain both simultaneously. They are classified based on whether they have DNA (DNA viruses) or RNA (RNA viruses).

**Hint:** Recall the classification of viruses based on their genetic material; they are either DNA or RNA viruses.

### Conclusion
After analyzing all the statements, we find that **Option 3** is the false statement regarding viruses.

**Final Answer:** Option 3 is false: "Viruses cannot pass bacterial proof filters."