They usually use ear tags
The answer is; To enhance desirable traits in an organism or switch off undesirable traits.
The transgenic organism has modified genome that alters its behavior. These organisms can be used in medical research in the laboratory or can be used for commercial purposes. An example of a transgenic organism is a GMO plant or bacteria that produce insulin.
Question 2 is false because it is always opposite.
Question 3 Ionic charge in which valence electrons are lost from one atom and gained by another one hoped it helped.