How did the native communities of the southeastern Canada convey information to one another? In general, they used messengersmemorized oral messages. Among some peoples, the Iroquois and the Algonquians for example, messengers also used code based on strings of beads. The beads were called "wampum" and the color of the beads signified the message. For instance, white beads were used for news of peace, prosperity, or good will. Purple beads meant war, disaster or death. The messengers also carried messages for early European explorers and missionaries. One missionary described in his journals how a messenger memorized 20 different detailed transactions, delivered them to Montreal and then returned with exact what price to each. He had traveled 800 miles round trip. Sometimes the messages were written, not oral and will be. passed from one messenger to another. When one messenger arrived to the edge of his tribe's territory, he would sell the letter to the next messenger, usually at a profit. If the letter passed through many hands before reaching the receiving end, the final bill could be very expensive.
解析
What is the main topic of the talk?
主旨题。根据讲座的首句How did the native communities of the southeastern Canada convey information to one another ?In general，they used messengersmemorized oral messages．可知主要讲的是加拿大东南部社区群落是如何传递消息的。因此。正确答案是B。