Recently, researchers uncovered the molecular structure of a key protein that retroviruses use to multiply. this was a significant step toward
a.) producing lifelike artificial limbs
b.) providing healthcare for all people
c.) stopping the spread of the hiv/aids virus
d.) using biotechnology to vaccinate children

Recently, researchers uncovered the molecular structure of a key protein that retroviruses use to multiply. This was a significant step toward using biotechnology to vaccinate children.    


Biotechnology is the use of living systems and organisms to develop or make products, or "any technological application that uses biological systems, living organisms or derivatives thereof, to make or modify products or processes for specific use" (UN Convention on Biological Diversity, Art. 2).  

The correct answer between all the choices given is the last choice or letter D. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.