The main purpose of the last line of the passage is to signal the reader that steps will follow.
In the first part of the passage, the author is giving some <em>background information</em> about the topic, which functions as an introduction to develop the main topic. The last sentence serves <em>to trigger</em> what the passage is actually concerned in, that is, the different ways in which contamination by this bacterium can be avoided. Thus, what the reader is expecting after the last line are some steps to follow.
In "The Hobbit", by J.R.R Tolkien, in the later part of the book (or the third movie), the battle of the four armies, the humans under the leadership of Bard, and the Elvish soldiers under their king teamed up to drive Thorin & Co. into giving them their share of gold. However, as events transpire, the orcs under Bolg(?) invaded the mountains in an effort to defeat the rest of the races, prompting the people of the lake, the elves, and the dwarves to team up in the fight. Before the orcs arrived though, Bilbo was stuck with the dwarves in the mountain, and wishes for his home. To make all sides happy, he decided to steal the "Arkenstone" ( the stone that is precious to Thorin, and 'is his heart'), and give it to the humans and elves as a bargain for their share of gold. However, things do not happened as planned, as Bilbo is banished from the castle, and the orcs arrive, prompting the humans, elves, and dwarves, to fight together, in the battle of the three armies. So no, while Bilbo was able to somewhat stop the war between the dwarves and the humans & elves, he was not able to stop the larger war, the battle of the three forces combine vs the orcs.
Hope this helps
Answer:Chapter 31 of to kill a mockingbird made me feel sad. The part when Scout goes inside his house, and Boo never sees him again made me feel sad. What surprised me is that the book makes no return to the adult Scout for closing narration, and Lee offers the reader no details of Scout’s future except that she never sees Boo again.