What computer component is also known as "the brains of the computer"?

What types of physical data storage are there?

What type of data storage is volatile?

what type of data is non-volatile?

The CPU generates a lot of heat when calculations are being performed. what component is used to keep the CPU cool?

what is the use of a dedicated graphics card when an integrated graphics card is already built into the computer?

while playing games alone is fun, the beauty of most games is the online functionality. what component of the PC would enable this?