Why do the cars need oil for their operation?

Why do the cars need oil for their operation?

Besides the gasoline, the cars need oil for their correct operation.
The motor produces some explosions that originate gases, the force of these gases it impels a piece called piston.
The piston transmits the force until ending up being applied to the turn of the wheels.
The oil is necessary because, these pushes produce frictions and increases of temperature that could damage the pieces of the motor.
Mineral oil is used that lubricates them when introducing it among the pieces, allowing that they slip easily and this way to conserve them under good conditions.