(2) Under normal circumstances, the fertilization site in mammals is fallopian tube, where fertilized eggs will develop early embryos and then implant into endometrium to continue to develop into new individuals. Therefore, fertilized eggs with rat growth hormone gene should be injected into fallopian tubes in the experiment.
(3) Transgenic mice developed from fertilized eggs with rat growth hormone gene are 2-3 times faster than those born with siblings, which indicates that the size of mice is controlled by genes.
So the answer is: (1) transgenic technology; microinjector
(2) fallopian tubes; womb
(3) Gene