What is vaccine

Options

A. Treated bacteria, virus & protein
B. Treated algae
C. Treated fungi
D. Treated plasmodium

Answer

### Step-by-Step Solution:

1. **Definition of Vaccine**: A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease. It typically contains an agent that resembles a disease-causing microorganism.

2. **Purpose of Vaccines**: The primary purpose of a vaccine is to train the immune system to recognize and combat pathogens, such as bacteria and viruses. This training helps the body to produce antibodies that will fight off the actual pathogens if encountered in the future.

3. **Composition of Vaccines**: Vaccines are made from treated forms of pathogens. This can include:
- **Treated Bacteria**: These are killed or weakened forms of bacteria that cannot cause disease but can still provoke an immune response.
- **Treated Viruses**: Similar to bacteria, these are either inactivated or attenuated viruses that stimulate the immune system without causing illness.
- **Proteins**: Some vaccines contain specific proteins from pathogens that can elicit an immune response.

4. **Types of Vaccines**: There are various types of vaccines based on their composition:
- **Inactivated or Killed Vaccines**: Contain pathogens that have been killed or inactivated.
- **Live Attenuated Vaccines**: Contain live pathogens that have been weakened.
- **Subunit, Recombinant, or Conjugate Vaccines**: Contain pieces of the pathogen (like proteins) rather than the whole germ.

5. **Conclusion**: Based on the information provided, the correct answer to the question "What is a vaccine?" is that it is made from treated bacteria, viruses, and proteins. Therefore, the answer is option A.