Researchers are trying to make a genetically modified (gm) pig that expresses bovine (cow) growth hormone to make it grow bigger. they isolated the bovine growth hormone gene, cut it and a plasmid with the same restriction enzyme, and mixed them together. they inserted the mixture into pig zygotes, but only normal pigs, not gm pigs, grew. what did they likely do wrong?

In the given case, the researchers forgot to add DNA ligase after amalgamating the plasmid and gene together. DNA ligase refers to an enzyme, which repairs breaks or abnormalities in the backbone of double-stranded molecules of DNA.  

It performs three prime activities, that is, it seals the recombination fragments, seals repairs in the DNA, and its associates or interlinks the Okazaki fragments, which are the small fragments of DNA produced at the time of the replication of the double-stranded DNA. As the mentioned procedure lacks the activities of DNA ligase, due to which only formation of normal pigs took place not the genetically modified pigs.  

i think that d. wind is the answer.   i missed the question when i answered a. currents.