(a) - Humoral immune response: This response involves the production of antibodies by B cells to neutralize pathogens and prevent infections. It is primarily mediated by the action of antibodies in bodily fluids.
- Cell-mediated immune response: This response is carried out by T cells, particularly cytotoxic T cells, which target and destroy infected cells or cancerous cells. It does not involve antibodies.
(b)

- An antibody molecule has a “Y” shaped structure with two heavy chains and two light chains.
- Variable region: Located at the tips of the Y, it binds to the antigen.
- Constant region: The stem of the Y, which determines the class of antibody (IgG, IgM, etc.).
- Hinge region: Located between the arms of the Y, allows flexibility.
- Disulfide bonds: Hold the heavy and light chains together.

| S. No. | Particulars | Amount (in ₹ crore) |
|---|---|---|
| (i) | Operating Surplus | 3,740 |
| (ii) | Increase in unsold stock | 600 |
| (iii) | Sales | 10,625 |
| (iv) | Purchase of raw materials | 2,625 |
| (v) | Consumption of fixed capital | 500 |
| (vi) | Subsidies | 400 |
| (vii) | Indirect taxes | 1,200 |