Final answer:
Will develops genuine feelings of love for Rachel, while Marcus has a complex but emotionally impactful relationship with Ellie. Both relationships catalyze significant changes and emotional growth in Will and Marcus, highlighting the transformative power of personal connections in 'About a Boy'.
Step-by-step explanation:
The feelings that Will and Marcus have for Rachel and Ellie in 'About a Boy' are complex and evolve over the course of the novel. In the case of Will, he initially falls for Rachel and their relationship leads to him experiencing genuine love, which is a significant change from his previous commitment-phobic lifestyle. Meanwhile, Marcus begins to see Ellie as more than just a friend; though their relationship is complicated by Ellie's issues, it inspires Marcus to grow emotionally and to advocate for himself more.
The relationships that Will and Marcus form with Rachel and Ellie, respectively, are critical in their character development, showing how personal connections can lead to self-discovery and emotional maturity. Will learns to care for others beyond himself, making his relationship with Rachel an important part of his growth. Similarly, despite any challenges within their dynamics, Ellie's influence on Marcus prompts him to become more confident and to stand up for what he believes in, demonstrating significant emotional growth.