A) lower survival rate offsprings can only explain why GM genes didn't propogate
B) if this is true it means genetically modified salmon exists in the river and may interbred also
C) if genetically modified escape into oceans, it doesn't means there interbred offsprings will also do so
D) after first spawning season GM genes found in offsprings, which means migrating to distant doesn't explain absence of genes
E) even fewer genetically modified salmon can change the genes of offsprings if they interbred actively
BunuelA research team discovered that a species of genetically modified (GM) salmon had escaped from a nearby aquaculture facility and interbred with wild salmon in a local river system. In the first spawning season after the escape, genetic testing of juvenile wild salmon confirmed the presence of GM genes. The facility was then shut down and all remaining GM salmon were removed. Three years later, a follow-up study that sampled hundreds of wild salmon found no trace of GM genes.
Which of the following, if true, most helps to explain the discrepancy between the two studies?
A. Offspring of genetically modified and wild salmon had significantly lower survival rates in the river environment than offspring of two wild salmon.
B. Natural predators tend to avoid genetically modified salmon because of differences in their taste.
C. Genetically modified salmon are more likely to escape into ocean environments than remain in rivers.
D. Wild salmon in the river system typically migrate to distant spawning grounds and return only every few years.
E. Fewer than ten adult GM salmon escaped before the facility was closed.