Passive immunity is one which is obtaines by injection

Options

A. Antibiotics
B. Vaccines containing weakened germs
C. Antibodies
D. Antigens

Answer

**Step-by-Step Solution:**

1. **Understanding Passive Immunity:**
- Passive immunity is a type of immunity that is acquired when antibodies are transferred from one individual to another. This can occur naturally or artificially.

2. **Natural Passive Immunity:**
- An example of natural passive immunity is the transfer of antibodies from a mother to her fetus. This occurs in two ways:
- Through the placenta during pregnancy.
- Through breast milk (specifically colostrum) after birth.

3. **Artificial Passive Immunity:**
- Artificial passive immunity involves the injection of antibodies from one person into another. This method is used to provide immediate immunity to the recipient.
- A common example of artificial passive immunity is gamma globulin injections, which contain antibodies.

4. **Analyzing the Options:**
- The question provides four options to identify which one represents passive immunity obtained by injection:
- **Option 1: Antibiotics** - Incorrect. Antibiotics are drugs used to kill bacteria and do not provide immunity.
- **Option 2: Vaccine containing weakened germs** - Incorrect. Vaccines stimulate the immune system but do not provide passive immunity.
- **Option 3: Antibodies** - Correct. Antibodies can be injected to provide passive immunity.
- **Option 4: Antigens** - Incorrect. Antigens are substances that trigger an immune response but do not confer passive immunity.

5. **Conclusion:**
- The correct answer to the question is **Option 3: Antibodies**, as they are the components injected to provide passive immunity.

---