Test Imat 2019-2020: quiz di Cultura generale e ragionamento logico

Domande ufficiali di Cultura generale e Regionamento logico proposte dal Miur al test IMAT 2019-2020

Domanda 5 di 22

Researchers have tried to establish reasons for a recent drop in the catch of marlin near the Madeira coast. This drop cannot be explained by environmental conditions; there was no significant change in the temperature or composition of the region’s water. Nor could one blame the human factor, because the size of the fishing fleet, catch quotas and pollution levels have been strictly observed. The environmentalists then analysed the records of the fishing catch of marlin over the last six centuries. This research identified that regular five-year periods of significant decrease in the catch alternated with fifteen-year periods of gradual growth of the catch. In view of this, the study concluded that the current drop in the marlin catch is part of a long-term cycle related to fish migration and food-chain balance.

Which one of the following is an underlying assumption of the above argument?