In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

What did NBC delay for the west coast primetime?, Context: CBC's sports coverage has also attained high viewership in border markets, including its coverage of the NHL's Stanley Cup Playoffs, which was generally considered to be more complete and consistent than coverage by other networks such as NBC. Its coverage of the Olympic Games also found a significant audience in border regions, primarily due to the fact that CBC aired more events live than NBC's coverage, which had been criticized in recent years for tape delaying events to air in primetime, even if the event is being held in a market in the Pacific Time Zone during primetime hours on the East (where it would still be delayed for West coast primetime).
Olympic Games

What is not a source of interspersed repeats: transposable elements or genome evolution?, Context: Interspersed repeats mainly come from transposable elements (TEs), but they also include some protein coding gene families and pseudogenes. Transposable elements are able to integrate into the genome at another site within the cell. It is believed that TEs are an important driving force on genome evolution of higher eukaryotes. TEs can be classified into two categories, Class 1 (retrotransposons) and Class 2 (DNA transposons).
genome evolution

What elements of the properties of QED vacuum don't exist physically?, Context: QED vacuum has interesting and complex properties. In QED vacuum, the electric and magnetic fields have zero average values, but their variances are not zero. As a result, QED vacuum contains vacuum fluctuations (virtual particles that hop into and out of existence), and a finite energy called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some experimentally verified effects of vacuum fluctuations include spontaneous emission and the Lamb shift. Coulomb's law and the electric potential in vacuum near an electric charge are modified.

virtual particles