In this lesson, we discussed expansion cards and their various interfaces, emphasizing the importance of compatibility with the motherboard. Students will learn to select the correct expansion card, justify their choices, and differentiate between different expansion technologies and interfaces, including AGP, PCI, PCI-E, and M.2. The lesson highlights that graphics cards, network cards, and sound cards are common types of expansion cards, each serving different performance needs. Understanding these components is crucial for optimizing computer performance and ensuring proper upgrades.