The basic component inside the system unit is the Central Processing Unit.
processor
With solder and hot-melting glue.
power supply HDD floppy disk drive
System unit refers to the housing plus the components inside the box. While a computer case is just a 'case' itself w/o the hardware components attached to it.
cars
system unit is used to control the parts of the computer system
These are located in the system unit or processing unit.
Cpu: central processing unit alu: arithmetic and logical unit memory processor i/o devices
System Unit
The components that process data are located in the system unit
System unit