(a) For less than 8 cells, blastomere is transferred to the fallopian tube.
For more than 8 cells, blastomere is transferred to the uterus.
(b) Embryos with more than 8 cells are generally considered healthier and have a better chance of successful implantation and further development and hence are placed in the uterus and not the fallopian tube.
(c) For less than 8 cells, zygote intra-fallopian transfer is done.
For more than 8 cells, the intra-2 uterine transfer is done.