Which of the following is an important infectious disease in humans?

Identify the molecules $(A)$ and $(B)$ shown below and select the right option giving their source and use.
| Molecule | Source | Uses |
| :--- | :--- | :--- |

$A$ - Smoking increases $O_2$ content in blood.
$R$ - Nicotine stimulates the adrenal gland.

After infection by pathogens,dead cells,dead pathogens,and liquid form the:

Identify the number of correct statements from the following:
$(1)$ Gene therapy is used in the treatment of $ADA$ deficiency.
$(2)$ Tetanus causes sustained muscle contraction. There is a lack of relaxation phase.
$(3)$ Cigarette smoking leads to asthma in the respiratory system.
$(4)$ $A$ transplanted kidney in a patient can fail due to cell-mediated immunity.
$(5)$ Serum globulin is an antibody.

Pests resistant to insecticides have: