Which is the best use of punctuation? many people are squeamish around, insects, and rodents. our instructor taught us techniques (to us) master welding. upon hearing her diagnosis, she was filled with one emotion: relief. the children in her afterschool class tend to be immature (and silly).

The answer is:

Upon hearing her diagnosis, she was filled with one emotion: relief.

In the chosen sentence, the comma is properly used when the sentence begins with a time reference. Besides, the colon is used to provide an explanation, illustration or extension, such a as the exact emotion she wishes to express - relief.

The rest of the alternatives are incorrect because the commas are wrongly placed and the brackets are unnecessary.

Upon hearing her diagnosis, she was filled with one emotion: relief.

research question: do the predicted benefits of genetic enhancements outweigh the possible negative consequences of this technology?  

what information do i need to research in order to answer this question?  

-predicted benefits of genetic enhancements

-negative consequences of genetic enhancements

-existing, if any, consequences of the new technology

-possible consequences if the technology is perfected

what sources will have the information?

-scientific research documents or news articles summarizing research

-articles in science and medical journals, magazines, and electronic databases

-books

-experts at genetics: geneticists, scientists, professors

here you go have a nice day