Multics was the first operating system to integrate security as its core functions.
I'd go for <span>
FLOOR(x) </span>
The numerical function FLOOR(x) can be used to return the
largest integer value that is less than or equal to the numerical expression
provided. The numerical function CEILING (x) is the opposite of FLOOR(x) since
it gives the smallest integer value that is greater or equal to the numerical
expression.
This is true because the motherboard is the main holder of all the operation and connection of all the system.
The answer to this is Optical mouse.
The reason the answer is optical mouse is because the optical mouse is a computer mouse which uses a light source, typically a light-emitting diode, and a light detector, such as an array of photodiodes, to detect movement relative to a surface.
Hope this helped :)
have a great day