What is commonly referred to as the "brains" of a computer?

The microprocessor is often referred to as the "brains" of a computer because it is the main component that executes instructions and performs calculations necessary for running programs. It processes data by following a set of instructions provided by the software, effectively managing tasks and coordinating activities within the computer system. The microprocessor is responsible for interpreting and executing program commands, making it central to the computer's functionality and performance.

In contrast, RAM is important for temporarily storing data and instructions that the microprocessor needs while performing tasks, but it does not execute instructions itself. The hard drive serves as the long-term storage of files and applications, housing data even when the computer is turned off, without being involved in processing it. The power supply provides the necessary electrical power to all components of the computer but plays no role in computing processes. Thus, the microprocessor's role in executing commands and performing calculations justifies its title as the "brains" of the computer.