What is required to allow the use of expansion cards in a computer?

To allow the use of expansion cards in a computer, the most critical component is the motherboard. The motherboard serves as the central printed circuit board that connects all hardware components of a computer, including the central processing unit (CPU), memory, storage devices, and various expansion cards like graphics cards, sound cards, and network cards.

Expansion cards require slots on the motherboard—such as PCI Express slots—for installation. These slots provide both the physical space necessary to hold the cards and the electrical connections needed for communication between the cards and the motherboard. If the motherboard does not have the appropriate slots, expansion cards cannot be added to enhance or modify the computer's capabilities.

In contrast, while the CPU and power supply are essential for the overall operation of the computer, they do not directly facilitate the addition of expansion cards. The cooling system, while important for maintaining optimal temperatures and preventing overheating, also does not inherently enable the use of expansion cards. Hence, the motherboard is the key component that supports the integration of expansion cards into a computer system.