How are June and Day the same and different?

In Part I, we come to see that although June and Day come from very different backgrounds, they both have similar motivations. June and Day both value their siblings deeply. Now that we know more about Tess, it is clear that her relationship with Day is similar to June’s relationship with Metias. Both pairs were forced to grow closer in order to cope with difficult circumstances. In both situations, the older boy mentors the younger girl. Like Metias, Day teaches his younger "sister" survival skills that will help her live independently after they are separated.