what i a cpu?

Answer:

It's the computer's brains
CPU is short for Central Processing Unit. The CPU can be thought of as the brains of the computer system. Often culture mistake the case or chassis of their computer as the CPU. The CPU is certainly an internal component of the computer that can not bee seen from the outside of the system, or the inside in need removing the CPU heatsink and fan. A CPU is commonly the most expensive component of a computer and is awfully sensitive to static electricity.
a CPU is a Central Processing Unit, a bit like a brain but within a pc "Processor"
Central Processing Unit, the computer wants a place to house the motherboard, cards and drives, kindof like a brain but still a computer.