The motherboard serves as a single platform to connect all of the parts of a computer together.
ROM stands for Read Only Memory. The memory from which we can only read but cannot write on it. This type of memory is non-volatile.
RAM(Random Access Memory) is the internal memory of the CPU for storing data, program and program result. It is read/write memory which stores data until the machine is working. As soon as the machine is switched off, data is erased.
A memory is just like a human brain. It is used to store data and instructions.
CPU is considered as the brain of the computer.