Final answer:
Novinha and Ender are connected by their mutual isolation and the need for understanding, which is deeply rooted in their unique abilities and experiences, leading to their eventual union.
Step-by-step explanation:
The common thread that binds together the stories of Novinha and Ender is the theme of isolation and the struggle for understanding and acceptance. Both characters are set apart by their exceptional abilities and circumstances, which leads to them feeling alone in their respective societies. Yet, it is this very uniqueness and the shared experience of being misunderstood that draws them together. For Novinha, it's the early loss of her parents and her access to classified scientific information that isolates her from her peers. Similarly, Ender is segregated due to his prodigious tactical mind and the burden of expectations placed upon him. Both characters have to navigate complex emotional landscapes and confront internal and external challenges that ultimately lead to their union.