The Motherboard
In a computer there are many things working and processing to keep it running efficiently. The motherboard's main purpose is to hold and connect hardware called chips together. Lots of chips are mounted on the motherboard and the most important one is the CPU. But the CPU can't function without memory to access and process so ROM or RAM is used.
Here is a labelled picture of the motherboard. You can see all the chips and ports connected. The motherboard allows all of these to communicate.
Mother boards can get quite hot when working and are usually cooled with heat sinks. Heat sinks are heat exchangers. A heat sink disperses heat away from whatever it is being used on. Heat sinks are used so that your computer does not overheat or crash, which could potentially break your computer and information.