The reading passage and the speaker both discuss strange noises found by Russian submarines. The article provides three possible theories. However, the scholar casts doubt on all points mentioned in the passage.
First of all, the reading passage maintains that the sound might have come from Orca whales during a courtship ritual. Nonetheless, the lecturer contradicts the point by arguing that Orca whales were living on the surface of water, yet submarines were sunk in the deep ocean, and it was impossible for submarines to hear sounds on the surface. Moreover, whales were detectable by sonar if they were nearby submarines. Apparently, it is unlikely that the sounds came from Orca whales.
Secondly, the article states that the sounds might have been made by giant squid as this marine creature lived deep in the ocean and difficult to detect by sonar. Nevertheless, the professor refutes the statement by mentioning that the sounds started from 1960 to 1980. Yet, the voices disappeared afterwards. On the other hand, giant squid always lived in the deep ocean. Therefore, it is impossible for squids to make sounds for two decades, and stop making the sounds for another two decades.
Lastly, the article believes that the sounds might have been stray sounds from some military technology from other countries. Once again, the lecturer contends that foreign submarines could not move quickly. Furthermore, the sounds of engines from submarines could not be similar to froglike sounds. As a result, it is unlikely that the weird sounds came from other submarines.
To conclude, the lecturer successfully refutes all of the theories presented in the passage. That is to say, he maintains that the strange sounds could not caused by Orca whales, giant squid, and foreign submarines.