Read the following matches and mark the correct option :
I. Antigen binding site on antibody : contains a variable region of a heavy chain only
II. Humoral immunity: due to antibodes, secreated by plasma cell
III. Graft rejecation: due to cell-mediated immunity response
IV. Colostrum : provides active immunty to infacts or newborns.

Options

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

Answer

To solve the question, we need to analyze each of the statements provided and determine if they are correct or incorrect. Let's break it down step by step:

### Step 1: Analyze Statement I
**Statement I:** Antigen binding site on antibody: contains a variable region of a heavy chain only.

- **Analysis:** This statement is incorrect. The antigen binding site on an antibody is formed by the variable regions of both the heavy and light chains. Therefore, it is not limited to the heavy chain only.

### Step 2: Analyze Statement II
**Statement II:** Humoral immunity: due to antibodies secreted by plasma cells.

- **Analysis:** This statement is correct. Humoral immunity is indeed mediated by antibodies that are produced and secreted by plasma cells.

### Step 3: Analyze Statement III
**Statement III:** Graft rejection: due to cell-mediated immunity response.

- **Analysis:** This statement is correct. Graft rejection occurs due to the cell-mediated immune response, where T-cells recognize the graft as foreign and mount an immune response against it.

### Step 4: Analyze Statement IV
**Statement IV:** Colostrum: provides active immunity to infants or newborns.

- **Analysis:** This statement is incorrect. Colostrum contains antibodies that provide passive immunity to infants, not active immunity. Active immunity is developed through the immune system's response to pathogens, while passive immunity is provided through the transfer of antibodies.

### Conclusion
Now, let's summarize the correctness of each statement:
- Statement I: Incorrect
- Statement II: Correct
- Statement III: Correct
- Statement IV: Incorrect

### Final Answer
The correct option based on the analysis is that **only Statements II and III are correct**.