Read the following statements and select the correct ones.
(i) Vaccine is a preparation (or suspension ) of a dead/attenuated pathogen of a disease which on inoculation ( or injection ) into a healthy person, provides temporary/permanent active immunity by inducing antibodies formation.
(ii) Immunisation is the process by which the body produces antibodies against the vaccine preventable diseases through administration of specific vaccines.
(iii) The principle of immunisation or vaccination is based on the property of 'memory' of the immune system.
iv) If a person is infected with some deadly microbes to which quick immune response is required; in that case, we need to directly inject the performed antibodies or antitoxins e.g., in case of tetanus.

Options

A. (i) and (ii)
B. (iii) and (iv)
C. (i), (ii) and (iii)
D. (i),(ii),(iii) and (iv)

Answer

To determine which statements are correct regarding vaccines, immunization, and the immune response, let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement (i)**: "Vaccine is a preparation (or suspension) of a dead/attenuated pathogen of a disease which on inoculation (or injection) into a healthy person, provides temporary/permanent active immunity by inducing antibodies formation."
- **Analysis**: This statement accurately describes what a vaccine is. Vaccines can be made from dead or attenuated (weakened) pathogens. When administered, they stimulate the immune system to produce antibodies, leading to active immunity. This immunity can be temporary or permanent depending on the type of vaccine.
- **Conclusion**: This statement is **correct**.

2. **Statement (ii)**: "Immunisation is the process by which the body produces antibodies against the vaccine preventable diseases through administration of specific vaccines."
- **Analysis**: This statement correctly defines immunization. It is indeed the process through which the body generates an immune response, specifically the production of antibodies, in response to vaccines that prevent certain diseases.
- **Conclusion**: This statement is **correct**.

3. **Statement (iii)**: "The principle of immunisation or vaccination is based on the property of 'memory' of the immune system."
- **Analysis**: This statement is true. The immune system has a 'memory' component that allows it to remember pathogens it has encountered before. This memory enables a faster and more effective response upon re-exposure to the same pathogen, which is the basis for how vaccines work.
- **Conclusion**: This statement is **correct**.

4. **Statement (iv)**: "If a person is infected with some deadly microbes to which quick immune response is required; in that case, we need to directly inject the performed antibodies or antitoxins e.g., in case of tetanus."
- **Analysis**: This statement describes a situation where immediate protection is needed, such as in the case of tetanus. In such cases, passive immunity can be provided by injecting pre-formed antibodies (antiserum) to provide rapid protection against the disease.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
All four statements (i, ii, iii, and iv) are correct.