Which component acts as the 'brain' of the computer?

The central processing unit (CPU) serves as the 'brain' of the computer because it is responsible for executing instructions and processing data. It performs calculations, makes decisions, and manages the flow of information within the computer. The CPU interprets the commands from software applications and translates them into actions that the computer can perform, making it a crucial component in overall system performance.

In contrast, other options do not fulfill this role. The hard drive is primarily for storage, keeping files and data for long-term access. RAM (Random Access Memory) temporarily holds data that the CPU needs while performing tasks but does not process data itself. The motherboard acts as a platform that connects all essential components, including the CPU, but it does not execute instructions like the CPU does. This distinction underscores the unique role of the CPU as the central hub for processing and decision-making within a computer system.