Answer :
Answer:
1. There is a small sample of the disease that's being tried to prevent so that the body can get used to fighting it.
2. In the vaccine there is a small sample of a disease that the vaccine is being used to prevent. The white blood cells fight harmful bacteria and so prevent diseases.
3. A vaccine works by training the immune system to fight viruses or bacteria.
4. The antigenic variability of the virus and other viruses and bacteria acts as infective agents.
Answer:
1. There is a small sample of the disease that's being tried to prevent so that the body can get used to fighting it.
2. In the vaccine there is a small sample of a disease that the vaccine is being used to prevent. The white blood cells fight harmful bacteria and so prevent diseases.
3. A vaccine works by training the immune system to fight viruses or bacteria.
4. The antigenic variability of the virus and other viruses and bacteria acts as infective agents.