TPO 33 integrated writing skill

According to the reading passage, three theories were mentioned to show the purpose and meaning carved stone balls found in Scotland. While, in the listening section, lecturer stated that passage's arguments are not convincing, and he pointed out some competing theories, which contradict passage's information.
In the reading material, author mentioned three theories. First, carved stone balls were weapons used in hunting or fighting. Second, carved stone balls were used as part of primitive system of weights and measures. Finally, carved stone balls served as a social purpose as opposed to a practical or utilitarian one.
However, in the listening material, speaker pointed out three controversial theories. First, hunting weapons show signs of ware, so if carved stone balls were used in hunting or fighting, they would be cracked, while their surface is smooth and clear( without crack). Second, because carved stone balls were made of different types of stones, their density is different, even in equal shape and measures. Therefore, they have not been used as a tools for weights and measures. Finally, carved stone balls are unlikely to served a social purpose or elaborate designs, because those balls carved in intricate pattern. Besides, in past, when someone died, his relatives buried ornamental elaborate stones in his tomb, while there were carved stone balls buried in tombs and graves, so they could not use for that purpose.