Transgenic animals are routinely bred to carry human genes, or mutations in specific genes, thus allowing the study of the progression and genetic determinants of various diseases.
Transgenesis allows improvement of nutrients in animal products, including their quantity, the quality of the whole food, and specific nutritional composition.
Social researchers generally study ethics. they study human psychology for example. if they are biased in their surveys, that is not an ethical consideration.
D because the closer they are geneticaly, the more related they are. A cactus and a squirl have little to no similer genetic makeup so A human and a gibbon that already have a conspericy around them as to evolution would have closer makup.