None of the theories presented in the reading passage can explain whale beaching because each explanation leaves out some important information. First, the sickness theory, it makes sense that sick whales could become disoriented and end up trapped on land. But if this were a significant cause of beaching, we would expect most Beached whales to show signs of sickness. But when scientists examine the bodies of whales that have died from beaching, this is not what they find. In fact, the whales are usually found to have been free of serious disease at the time of their death. So sickness doesn't solve the mystery of whale beaching. Second, about military sonar, there seems to be some confusion in the reading passage during the sonar tests mentioned in the passage, the military used what's called a mid-frequency sonar, which uses sound waves from the middle of the sound frequency range. However, whales use low frequency sound waves for echolocation. It's unlikely that a mid-frequency military sonar would interfere with low frequency whale echolocation. These are two very different ranges of sound frequencies. So if there is any effect that military ships have on whales, it's not caused by the sonar. Third, the fact that whales sometimes beach during the periods of magnetic disturbances before earthquakes, does not necessarily prove that whale beaching’s and earthquake disturbances are closely linked. A lot of earthquakes occur every year, and many of them are not preceded by beaching’s. And it's also true that many beaching’s happen when no earthquakes are taking place. So the evidence for the magnetism theory is really pretty weak, just some isolated incidents and no regular correlation.