Smoking addiction is harmful because it produces polycyclic aromatic hydrocarbons, which cause

Amoebiasis is caused by

The treatment of snake bite by antivenom is an example of

Antibodies in our body are complex

The name of drug used in cancer treatment produced by biotechnology is

$A$ : Live attenuated vaccine is better in terms of immunity provided to the recipient.
$R$ : As secondary lymphoid organs, example peyer's patches are stimulated to protect the individual.