Explanation

Transgenic animals are made to carry genes which makes them more sensitive to the toxic substance then non-transgenic animals (i) Useful biological products can be produced by introducing into transgenic animals the portion of DNA (or genes) which codes for a particular product, $e.g.,$ human protein $(\alpha$-1-antitrypsin) is used to treat emphysema (ii) Brazzein is protein produced by a west African plant, Pentadiplandra brazzeana, which is approximately 2000 times as sweet as sugar. It is used as a low calorie sweetener. Local people have been using the super sweet berries of this plant for centuries. But the protein brazzein was patented in USA