Read the following statements and select the right option :
I. The spleen is a large bean-shaped organ, which mainly contains lymphocytes and phagocytic cells.
II. The principal of vaccination is based on the property of memory of the immune system.
III. The graft rejected or failure of organ transplantation is due to cell-mediated immunity .
IV. The yellowish fluid colostrum has an abundant amount of lgA antibodies which provide active immunity to newborn babies.

Options

A. I,II,III are correct
B. II, III, IV are correct
C. II and IV are correct
D. Only II is correct

Answer

To solve the question, we will analyze each statement one by one to determine their correctness.

### Step 1: Analyze Statement I
**Statement I:** The spleen is a large bean-shaped organ, which mainly contains lymphocytes and phagocytic cells.

- The spleen is indeed a large organ that is shaped like a bean. It plays a crucial role in the immune system by filtering blood and contains lymphocytes (B-cells and T-cells) and phagocytic cells (like macrophages).
- **Conclusion:** This statement is **correct**.

### Step 2: Analyze Statement II
**Statement II:** The principle of vaccination is based on the property of memory of the immune system.

- Vaccination works by exposing the immune system to a harmless form of a pathogen, which allows the immune system to "remember" the pathogen. This memory enables a faster and more effective response upon subsequent exposures.
- **Conclusion:** This statement is **correct**.

### Step 3: Analyze Statement III
**Statement III:** The graft rejected or failure of organ transplantation is due to cell-mediated immunity.

- Organ transplantation can indeed be rejected due to the immune response, particularly cell-mediated immunity. T-cells recognize the transplanted tissue as foreign and mount an immune response against it.
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze Statement IV
**Statement IV:** The yellowish fluid colostrum has an abundant amount of IgA antibodies which provide active immunity to newborn babies.

- Colostrum is the first milk produced by mammals after giving birth and is rich in antibodies. However, it primarily contains IgG antibodies, not IgA. IgA is present in breast milk but is not the predominant antibody in colostrum.
- **Conclusion:** This statement is **incorrect**.

### Final Evaluation
Now that we have analyzed all statements:
- Statement I: Correct
- Statement II: Correct
- Statement III: Correct
- Statement IV: Incorrect

The correct option would be the one that includes statements I, II, and III as correct.