Implementation of 8:1 MUX using MSI ICs

Which is the major functioning responsibility of the multiplexing combinational circuit?
If there are N numbers of select lines then state the numbers of input lines in the multiplexer?
Which digital circuit acts as switch.?
If select lines are S1 S0 = 11 then which of the input is selected by multiplexer?
One application of a digital multiplexer is to facilitate: