The five examples provided introductions to potential essays on various topics.
1) The first example introduced the topic of gray wolves in the U.S., arguing that they were wrongly eradicated but should now be protected and restored.
2) The second example introduced the topic of internet use among students, arguing that overreliance on the internet hurts intelligence while books enhance it.
3) The third example introduced a poem by William Butler Yeats, focusing on its themes of escaping hardship and seeking immortality.
4) The fourth example introduced the topic of CFCs and their threat to the ozone layer, arguing that global action is needed to reduce CFC use.