Please read following sentences carefully. Mark incorrect

Options

A. Injection of antiserum is artificial method to induce active immunity.
B. Skin cells forms cellular barriers of non specific immunity.
C. When our body is exposed to antigen for the first time, a slow and low intensity immune response is produced.
D. Blood group and tissue matching is done before transplantation.

Answer

### Step-by-Step Solution

1. **Understanding Active and Passive Immunity**:
- Active immunity occurs when the body produces its own antibodies in response to an antigen. This can happen naturally through infection or artificially through vaccination.
- Passive immunity involves the transfer of pre-formed antibodies from one individual to another, providing immediate but temporary protection.

2. **Analyzing the First Statement**:
- The first statement claims: "Injection of antiserum is an artificial method to induce active immunity."
- This statement is incorrect because the injection of antiserum provides passive immunity, not active immunity. Antiserum contains pre-formed antibodies that help fight off pathogens immediately but does not stimulate the body to produce its own antibodies.

3. **Evaluating Other Statements**:
- The second statement about skin cells providing non-specific immunity is correct. Skin acts as a barrier and is part of the innate immune response.
- The third statement regarding the immune response being slow and low-intensity during the first exposure to an antigen is also correct.
- The fourth statement about blood group and tissue matching before transplantation is correct, as mismatched blood or tissue can lead to an immune response against the transplanted organ.

4. **Conclusion**:
- The only incorrect statement is the first one about the injection of antiserum being an artificial method to induce active immunity. Therefore, the answer is that the first statement is incorrect.

### Final Answer
The incorrect statement is: "Injection of antiserum is an artificial method to induce active immunity."

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